Switched to basic python containers, onto which the ci
steps simply install poetry.
This takes a little more processing time during pipeline running (~16s
per step),
but also gives much more flexibility in container usage.
Switching to nox for test automation across multiple python versions.
Fixing mypy library stubs missing for some imported libraries.
Added basic continuous integration tests to run on any push.
On main branch, the python program is built.
On tagged commit, a gitea release is created.
Fixed build pipeline issues:
Ignored the typeless library imports nox and metadata_version since they
are for development testing and too old of a python version
respectively.
Fixed two small typing errors for repetitions.
