Modernize packaging and distribution

[lrq3000]

Although this package works, it's not bundled as a Python module as it should, which would tremendously ease installation and usage, especially for neophytes.

• Modern python package post pep 517
• Console alias entry to launch app from command-line without needing an explicit python call
• Semantic versioning
• Upload to pypi

Once this is done, a pyInstaller frozen build should be made, if possible cross-platform, maybe via cibuildwheel, see #5.

[lrq3000]

Done!