On documentation

[has2k1]

• Add link to documentation in the about section on the main page
• Add link to documentation in the readme
• Have 2 documentation destinations
  • Released / stable
  • Unreleased / main branch / latest
  • Make the versioning of the package under development clearly show that it is not a released version
• Prevent docs workflows initiated by PRs (esp. from contributors) from attempting to push to the gh-pages branch. Currently this happens and is indicated as a failed test

[isabelizimm]

I believe all tasks of this are complete with #93 . Feel free to reopen this or new issues for further docs updates!