Users and roles: Overviews, cloud org, project custom roles

[shainaraskas]

Users and roles PR #1. Part of https://github.com/elastic/docs-projects/issues/347

Does the following (click for preview :))

• writes overviews for:
  • users and roles section
    • ECE orchestrator section
    • Cluster or deployment section
      • cluster user auth section
      • cluster user roles section
• does full overhaul of:
  • cloud organization section (all child pages)
  • project custom roles page (now levelled up a bit for prominence)

cleans up raw files I used up and fixes links I broke, fixes some html stuff that was causing tests to fail

working on ECE/cluster in a separate PR to make this easier to review/merge

[eedugon]

Looks amazing, I love how the overviews look and how everything flows!
Just shared some minor comments, and approving anyway.

[eedugon]

Looks great!
I only saw something a bit weird, at the end of the cluster-or-deployment-auth/user-roles.md file:

For more information, see Document-level attribute-based access control with X-Pack 6.1.

I would remove X-Pack 6.1 from there.
I wouldn't even link such an old blog, but if we keep it at least I would remove the X-Pack mention, as it's not applicable anymore.

Anyway awesome work! Let's continue moving forward!!!