Add the twine upload to pypi and comgui.exe compilation to a separate 'release' azure pipeline path

[bajuwa]

This was originally deferred from the first azure pipeline ticket #69 for two reaons:

• the twine upload to pypi seems to stall in a way that's very similar to this bug: https://github.com/pypa/packaging-problems/issues/197
• it would be dangerous to have the release packaging occur automatically on changes to an active pull request as this might trigger a premature pypi release

Will need to be triggered manually using a variable in order to assign the appropriate version number