Use MkDocs Material Theme

[wesleyboar]

Proposal

Rebuild theme as customization of MkDocs Material theme, because that theme is better than the theme that the current one is based upon (MkDocs ReadTheDocs).

Why

It will fix many issues without tricks:

Issues logged in CMD-89 TACC Docs Use Better MkDocs Theme (internal, restricted).

It may fix these issues:

1. Navigation Scroll on Page Load

   [When I click] on an item in the nav, it scrolls the left nav up so that that item is that at the top... very disturbing and makes it hard to visualize the full section. — S

   Aye, it does. Sometimes it can not scroll item to top, and instead scrolls nav up as far as it can, with relevant item appearing in the middle of the nav. — W

   — feat: new account page, new nav section, smaller homepage DesignSafe-CI/DS-User-Guide#67 (comment)

[wesleyboar]

Theme in progress (TACC work on client with private docs).

wide

wide.mov

narrow	narrow - nav

narrow.mov