Quickboard

Major changes to usage include:
* Refactored how callbacks are handled for plugins eliminating the need to input `html_id`'s in constructors, as well as `parent_id`'s. These are now automatically handled by Dash.
* Updated the beginner example in the docs to reflect this change.
* Removed the `fig_postprocess` method for `PlotPanel`'s since the `plotter` input can be sufficiently customized to perform the same function

Minor release relaxing the versions required to install. In particular, allows for using Python 3.7 (e.g. in Terra notebooks).

Made a few small changes, including:
* Updated the README to use full links so the page still renders elsewhere, e.g. on PyPI;
* Added automation for releasing package to PyPI (and TestPyPI);
* Added `host` input for `start_app` to make more container-friendly.

Introducing Quickboard! Check out the [README](https://github.com/broadinstitute/quickboard/blob/main/README.md) and [Guided Example](https://github.com/broadinstitute/quickboard/blob/main/docs/beginner_example.md) to get started.

Note: This is pre v1.0.0, so expect major changes to occur in upcoming releases. For now, treat this as an experimental repo.