Remove Python implementation from main specification documentation

[RalfG]

• Remove Implementations section from the documentation (moved to it's own repo)
• Add workflow to deploy docs to GitHub pages (https://hupo-psi.github.io/mzSpecLib/) instead of readthedocs. The new home for the Python implementation docs is now at https://mzspeclib.readthedocs.io.

[mobiusklein]

I don't quite follow the deploy workflow's environment declaration mechanistically, but if I understand correctly this relinquishes the RTD configuration to mzspeclib-py, and then uses GitHub Pages to host the format documentation.

[RalfG]

I don't quite follow the deploy workflow's environment declaration mechanistically, but if I understand correctly this relinquishes the RTD configuration to mzspeclib-py, and then uses GitHub Pages to host the format documentation.

Exactly. GitHub Actions is now used to build the main documentation on the format with Sphinx and then pushes it to GitHub Pages with https://github.com/actions/deploy-pages. Documentation for mzspeclib-py is still build and published within the RTD system.