change(doc): Refactor user & dev docs

[upbqdn]

Motivation

Close #7890.

PR Author Checklist

Check before marking the PR as ready for review:

• Will the PR name make sense to users?
• Does the PR have a priority label?
• Is the documentation up to date?

For significant changes:

• Is there a summary in the CHANGELOG?
• Can these changes be split into multiple PRs?

Solution

• List Zebra crates in the landing docs for zebrad. The links in the list point to the docs of the public APIs on https://docs.rs.
• Change the search query for docs.rs. I noticed we currently search for zebra at https://docs.rs: https://docs.rs/releases/search?query=zebra. This query returns a lot of unrelated results. I figured searching for zebrad brings better results: https://docs.rs/releases/search?query=zebrad. However, none of these queries returns the two tower crates that belong the Zebra monorepo. I can't think of a suitable solution here.
• Additional maintanance cleanups unrelated to the issue:
  • Fix the rendering of expandable content. Right now, the expandable content in the Zebra Book looks like this:
    
    This PR attempts to fix that.
  • Refactor the docs refs in the readme
  • Refactor the landing docs for the zebrad crate
  • Remove ## Future Work from the main readme. This section doesn't say anything useful.

Reviewer Checklist

Check before approving the PR:

• Does the PR scope match the ticket?
• Are there enough tests to make sure it works? Do the tests cover the PR motivation?
• Are all the PR blockers dealt with?
  PR blockers can be dealt with in new tickets or PRs.

And check the PR Author checklist is complete.

[arya2]

Thank you!

[upbqdn]

The CSS hack that was supposed to fix the rendering of the expandable content actually worked:

It should work for the whole book from now on.