Utopya

- !41 implements `.plot.abm` which specializes on plotting output from agent-based models. Refer to the documentation for more information and examples.

- !39 fixes an error where auto-scaling in animated `caplot`s was done despite `vmin` and/or `vmax` being set.
- !40 adds `Parameter` shorthand modes `is-positive-or-zero`, `is-negative-or-zero`, and `is-in-unit-interval`.

- !37 fixes `caplot` for hexagonal grid structures, now supporting different hexagon orientations, offset modes and boundary options.
- !37 adds `imshow_hexagonal` as facet grid kind.
- !22 replaces utopya's `ColorManager` with the updated [dantro `ColorManager`](https://dantro.readthedocs.io/en/latest/plotting/color_mngr.html).
- !22 integrates the `ColorManager` into `caplot`, offering more ways to control colormaps and norms and fixing a number of subtle visual bugs.
- !22 fixes a bug in `GridDC` that led to data attributes being lost.
- !22 adds the `debug_level` option to the `Multiverse` and its meta configuration.
- For now, this does not do a lot, but it will be expanded to control more aspects depending on debug level.
- With `debug_level >= 2`, Python `DeprecationWarning`s are shown.

Deprecations
- !22 deprecates the `limits` argument for individual `caplot` properties; use the more conventional `vmin` and `vmax` instead.
- !22 deprecates the `draw_cbar` argument for individual `caplot` properties; use the more conventional `add_colorbar` instead.

- !36 fixes a critical bug that prevented installing utopya from PyPI.
- !36 removes minimum versions from requirements, making dependency resolution simpler.

Features and enhancements
- !28 improves error messages upon missing model executable.
- !31 implements the `utopya_backend` package which bundles classes and function that can be used to implement models.
- `BaseModel` provides shared simulation infrastructure like an RNG, signal handling, loggers, and a general scaffolding for running the model.
- `StepwiseModel` specializes `BaseModel` for models that make an "integer time" abstraction, with the `perform_step` method describing how to iterate the state.
- !31 improves handling of `WorkerTask`'s that were terminated due to a `StopCondition` signal.
- !32 adds the `utopya test MODEL_NAME` command to the CLI, making it easier to run associated Python model tests.
- !34 expands tests for drawing graphs using `.plot.graph`.

Bug fixes
- !30 fixes a bug that prevented re-running a `Multiverse` from the backed-up `meta_cfg.yml` file of a previous run.

Removals and deprecations
- !29 removes the (dysfunctional) `!model` YAML constructor; potentially to be re-added at a later point (discussed in 51).

This is the first *standalone* release of utopya.
With the standalone version, utopya can be used in more general contexts: Whenever you need to perform simulation runs from some executable and evaluate its outputs.

Prior to this release, utopya was only available as part of the [Utopia modelling framework](https://gitlab.com/utopia-project/utopia) and could not be used outside of it.

Features and enhancements
- !1 makes a number of substantial and backwards-incompatible changes that aim to improve package structure and maintainability:
- Apply code formatting using [black](https://github.com/psf/black)
- Implement the [pre-commit](https://pre-commit.com) framework to maintain consistent code formatting and allow other pre-commit hooks.
- Remove old-style plot functions and the legacy transformation framework
- Improve module structure, particularly by consolidating evaluation-related modules into a submodule
- !2 consolidates functionality related to stop conditions into a single module and provides the `stop_condition_function` decorator to simplify adding custom condition functions.
- !3 provides a demo model that illustrates the utopya model interface
- !3 reworks and simplifies parts of the model registry
- Require labels for model info bundles and allow specifying a default label
- Let `exists_action` only act on info bundles, not on model names
- !3 and !4 implement a more modern CLI using [click](https://click.palletsprojects.com/)
- All functionality is roughly maintained, but CLI syntax has changed in some places.
The legacy CLI is removed.
- Makes it much easier to expand the CLI and allows testing using pytest.
- Improves modularization by moving all CLI-related implementations into the new and separate `utopya_cli` package.
- Provides more ways to register models. In particular, there is now the option to register a model's metadata via a "model info file".
- !19 improves the implementation of `utopya models copy`, becoming more language-agnostic and extendable.
- !4 and !6 add a validated project registry, which keeps track of utopya projects (which in turn contain models) and frameworks: two abstraction levels that play a role in determining the configuration hierarchy.
- !24 improves the registry framework and the CLI to better handle corrupt project (or model) registry files.
- !5 adds changes that allow a proper [outsourcing of utopya from Utopia](https://gitlab.com/utopia-project/utopia/-/merge_requests/277):
- Extends the project registration CLI with `--require-matching-names` option.
- Allows to specify custom plot configuration pools via the meta-configuration.
- Allows to associate a project with a framework project.
- Adds new framework- and project-level configuration levels that are taken into account when compiling the Multiverse meta-configuration and the base plot configuration pools.
- !6 improves plotting functions:
- Adds `snsplot` for seaborn-based plots
- Modernizes the CA plot (`caplot`), now supporting the data transformation framework and deprecating the old `ca.state` plot
- !6 adds an extended demo model that showcases utopya usage for Python-based model implementations.
- !6 moves definition of custom config set search directories to the project-level and extends search to a wider set of model source subdirectories.
- !8 improves the package API documentation and includes intersphinx for cross-referencing to other packages.
- !9 adapts the package structure to the reworked dantro >= v0.18 interface
- This pertains mostly to the plotting framework. Due to utopya wrapping many parts of that interface, there are few backwards-*incompatible* changes.
- However, notice the [deprecations](https://gitlab.com/utopia-project/dantro/-/blob/master/CHANGELOG.md#v0180) introduced by dantro v0.18.
- !14 improves plot module pre-loading:
- Plot modules are now imported at the time of `PlotManager` initialization.
- Plot modules specified in the project and framework can be pre-loaded as well; this can disabled via the project `settings`.
- !18 expands the `ColorManager`, now allowing to specify continuous colormaps (using [`LinearSegmentedColormap`](https://matplotlib.org/stable/api/_as_gen/matplotlib.colors.LinearSegmentedColormap.html)).
- !21 updates and cleans up the base plots configuration, making use of the newly implemented dantro base plots config pool.
- !23 allows to store a model's project and framework repository states alongside the `Multiverse`'s backup for config files; this can help to reconstruct the state in which a model was run.

Internal
- !10 outsources `utopya._import_tools` to `dantro._import_tools`