GitLab basics overhaul: landing page
From @rdickenson's video teardown (https://www.youtube.com/watch?v=FSxCW75am0o) of https://docs.gitlab.com/ee/gitlab-basics/README.html, improve the basics landing page using the following notes:
- Too sparse for someone at the basic level. Needs to be fleshed out. Links to concepts handy.
- Lacks any context.
- Title says "GitLab Basics", but topic about Git also.
- A plain bullet list is not a good introduction to GitLab Basics.
Suggestions from video:
- Git be removed from here or linked out from here.
- Flesh out introduction. List and link to relevant concepts and content.
@rdickenson, could you do any refactoring of the bullet lists here you think are neccessary?
Relates to: https://gitlab.com/gitlab-org/gitlab-ce/issues/59815
TO DO:
MVC first, before changes to the page
Then another round this after the rest of the epic's issues are done.
CC @gl-docsteam