Pyvhdlmodel

Changes
* Renamed `Use` to `PackageReference`.

* Added documentation license (CC-BY 4.0)
* Updated and fixed badges (shields)
* Changed test runner to `pytest`
* Removed editor specific file headers (replaced by editorconfig)
* License screening and dependency check (also documented).
* Uploaded PyCharm project files and settings.

pyVHDLModel doesn't need latest Python 3.8 features.

pyVHDLModel was split from [pyVHDLParser](https://github.com/Paebbels/pyVHDLParser) v0.6.0.