Docs: batch of edits - Githubissues

This PR makes a number of edits to the docs that remove unnecessary content, improve styling and readability, and add cohesive language.

Removed the FAQ section. Details in the FAQ are given in the rest of the document so this is not needed.
Commented the Indices and tables section in the index to avoid rendering empty content
Changed the titles and removed 2nd and 3rd level headers to condense the text and improve overall flow.
Added a few edits to language that tie in with the arch diagrams in a separate PR.

ansible / ansible-sdk