Move gitlabpages to github pages

As a developer, I want to use github pages instead of Gitlabpages after moving to Github.

• Move documentation repository into Fed-BioMed repository under doc folder
• Auto generate document versions using Github workflow actions

A similar use-case: https://blog.esciencecenter.nl/versioned-documentation-using-only-github-actions-and-github-pages-1825296e31aa

Simple implementation:

• use branch gh-pages to keep static doc files (the build directory that is created after building mkdocs)
• use Github actions to push into this branh when a new version released