Add MKDocs

[SemyonSinchenko]

@MrPowers this PR adds docs in the same way like in other repos. Please make a look. Also it requires activating GH Pages from your side and also giving an action access to push into git (branch gh-pages).

Changes to be committed: new file: .github/workflows/mkdocs.yml modified: .gitignore new file: docs/gen_ref_pages.py new file: docs/index.md new file: mkdocs.yml modified: poetry.lock modified: pyproject.toml

[MrPowers]

@SemyonSinchenko - this is all setup now, thank you!