docs: overall minor renovations

[kurokobo]

SUMMARY

Live preview: https://ansible--1874.org.readthedocs.build/projects/awx-operator/en/1874/

This PR is overall minor renovation for documentation.

Main changes:

• Simplify and update README.md of this repository and use it as Home page of the doc site
• Correct levels of headings for the most pages
  • All pages begin with a level 1 heading. This makes the page toc to work properly.
    
  • Currently there is no toc because the level of headlines is too low.
• Use admonitions instead of text-based notes, tips, warnings, etc.
• Re-order navigations
• The content about hostAlias changed to a separate page
• Merge default-execution-environments-from-private-registries.md into deploying-a-specific-version-of-awx.md and change title to Using images from private registries
• Add an example to integrate LDAP via extra_settings_files on enabling-ldap-integration-at-awx-bootstrap.md
• Add existing pages to navigations: kind-installation.md, container-probes.md, security-context.md
• Remove adding-execution-nodes.md

Misc. changes:

• Add links to related pages on some pages (e.g. add link to minikube installation page on basic install page)
• Correct some misleading or out-of-date descriptions
• Move images under images directory
• Remove unused docs/awx-demo.svg
• Remove mailing list from Get Involved page
• Correct linting issues
• Fix indentation for some codeblocks
• Fix typos

ISSUE TYPE

• Bug, Docs Fix or other nominal change

ADDITIONAL INFORMATION

Live preview for this PR is here: https://ansible--1874.org.readthedocs.build/projects/awx-operator/en/1874/

[oraNod]

A couple of nits for you. Thanks for the docs renovations @kurokobo

[oraNod]

@kurokobo I don't know why the readthedocs project was not configured to generate build previews for PR but I've enabled that. If you'd like to close and reopen this issue, it should generate the preview for you now. Cheers.

[kurokobo]

@oraNod @tvo318
Hi, thanks for your comments! Sorry for the late reply, I haven't been feeling well and couldn't find the time to respond.
Will update this PR in next few days. Thanks!

[kurokobo]

@oraNod @tvo318
Thanks for reviewing this, I've updated this PR. Now ready for review again 😃
Live Preview: https://ansible--1874.org.readthedocs.build/projects/awx-operator/en/1874/

[oraNod]

Very minor nits. The rest looks great! Thanks so much @kurokobo

[kurokobo]

@oraNod
Thanks again, updated!