docs: refresh documentation structure

[bobheadxi]

Big refresh of the Rocket 2 docsite structure:

• more readme based on https://github.com/ubclaunchpad/inertia
• consolidate some pages (moved Scheduler to development tutorials), reorganize order
• simplify contributions
• document columns used in the Rocket 2 github project

Ticket(s)

closes #350

Details

pipenv shell
make html && serve ./_build/html   

[codecov]

Codecov Report

Merging #552 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #552   +/-   ##
=======================================
  Coverage   93.81%   93.81%           
=======================================
  Files          47       47           
  Lines        2669     2669           
  Branches      361      361           
=======================================
  Hits         2504     2504           
  Misses        108      108           
  Partials       57       57           

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[chuck-sys]

Docs: https://rocket2.readthedocs.io/en/rocket-refreshed/

[bobheadxi]

oh wow TIL readthedocs does branch previews!

[chuck-sys]

I'm looking through the docs (the ones that were touched the least) and a lot of things are out of date, one of which being one of the Development tutorials.

There will be a time for fixing these and updating them. But this PR is not one of them.

LGTM