Using mkdocs material as main page

https://squidfunk.github.io/mkdocs-material/ did quiet improve on building frontend pages. It would great to use the same technologies for both to have a consistent UX.

Review the existing JanusGraph website and the linked MkDocs Material reference to determine the current frontend structure and the proposed replacement scope. Done would mean adopting the referenced technology for the main page and achieving a consistent user experience, but the issue does not name files, tests, or a precise acceptance criterion.

Written by the indexing model from the issue text.