Octue

Summary
Switch to using `poetry` as a package manager instead of `pip`.

Among other things, this means dependencies are resolved once (at dependency addition time) instead of every time the package is installed, speeding up installations of `octue` in e.g. docker containers. This is done by recording the exact dependency versions `poetry` resolved in a `poetry.lock` file.

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Contents ([396](https://github.com/octue/octue-sdk-python/pull/396))

Operations
- Add `pyproject.toml` and `poetry.lock`
- Remove `setup.py` and `requirements-dev.txt`
- Update `tox.ini` to work with Poetry
- Update CI workflows and associated config files to work with Poetry
- Update `Dockerfile` to use Poetry
- Remove irrelevant `[dataflow]` extra specified in the Dataflow `Dockerfile`
- Create new `setup.py` file mirroring `pyproject.toml` in the `octue.cloud.deployment.google.dataflow` subpackage to allow Dataflow to continue to work (this must be updated alongside `pyproject.toml`
- Update python classifiers to include 3.7 and 3.9

Dependencies
- Upgrade to `Flask==2.0.3`

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Contents ([401](https://github.com/octue/octue-sdk-python/pull/401))

Dependencies
- Use `dateparser==1.1.1` in template to avoid `regex` package bug

Testing
- Re-enable temporarily skipped test
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Contents ([400](https://github.com/octue/octue-sdk-python/pull/400))
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Fixes
- Avoid mutating dictionary inputs
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Summary
Unify the configuration format in `octue.yaml` files for use as service configuration and for use by the cloud deployers.

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Contents ([397](https://github.com/octue/octue-sdk-python/pull/397))

Enhancements
- Unify deployer configuration with service configuration
- Warn user if there are unused kwargs in `ServiceConfiguration` or `AppConfiguration`

Operations
- Allow choice of branch in `build-docker-image` workflow

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Contents ([395](https://github.com/octue/octue-sdk-python/pull/395))

Fixes
- Use correct `octue.yaml` format when loading service configurations in `octue.configuration`

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Contents ([394](https://github.com/octue/octue-sdk-python/pull/394))

Dependencies
- Explicitly require the `PyYAML` package

Operations
- Set `GOOGLE_CLOUD_PROJECT` envvar for CI testing to avoid polluted logs

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