docs: simpler readme + add small docs

[wesleyboar]

Overview

Simplify the README. Add supplemental docs.

Note
I suggest reading the new README.md without the diff.

Related

• similar format to docs: better readme + add small docs Core-CMS-Resources#182
• similar format to https://github.com/TACC/Core-CMS-Custom#readme

Changes

• changed /README.md to be much better
• added /docs to hold README excess

Testing

1. Evaluate the README.md without the diff.
2. Read through the new files within the diff.
3. Review docs: better readme + add small docs Core-CMS-Resources#182.

UI

N/A

[fnets]

I don't know much about the non-APCD CMS sites, but this makes sense

[wesleyboar]

I had been mimicking https://github.com/TACC/Core-Portal README format as closely as possible, but CMS is ready for its own README format, and this documentation update coincides well with https://github.com/TACC/Core-CMS/releases/tag/v3.12.0 and the deprecation of https://github.com/TACC/Core-CMS-Resources ¹ and the increasing migration to https://github.com/TACC/Core-CMS-Custom ¹.

Footnotes

1. These repos have similar style README's to this PR's README. ↩ ↩²