Deprecate /capabilities/{{name}}

[ocket8888]

What does this PR (Pull Request) do?

Depends on PR #3870

• This PR resolves Rewrite /capabilities/{{capability}} to Go #3822

Adds deprecation notices to the output bodies of all method handlers for /capabilities/{{name}} as well as to the documentation. Also adds a new Mojo helper to add deprecation notices to responses that already have alerts and also don't have alternative routes.

Which Traffic Control components are affected by this PR?

• Documentation
• Traffic Ops

What is the best way to verify this PR?

Build and run Traffic Ops and make sure the /capabilities/{{name}} endpoint works and outputs the correct deprecation notices. Build and read the documentation to ensure it builds and is correct and thorough.

The following criteria are ALL met by this PR

• I have explained why tests are unnecessary
• I have explained why documentation is unnecessary
• This PR includes an update to CHANGELOG.md
• This PR does not include a database migration
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY

[asfgit]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/trafficcontrol-PR/4169/
Test PASSed.

[mhoppa]

based on https://lists.apache.org/thread.html/cfd3a6d631f2c7510e3a15ee051840a9f04f3f0aa0c2696e460c9ab9@%3Cdev.trafficcontrol.apache.org%3E should this be closed and redone as a deprecate message on the perl route?

[ocket8888]

That thread never reached a decision as to whether or not deprecated routes ought to be rewritten. If a decision to not rewrite these handlers is reached I'll close this PR (assuming it's still open), in the meantime I guess it's in the hands of people browsing PRs whether or not this is worth merging (once it isn't a draft (if ever)).

[mhoppa]

do we need to get convergence on that prior to moving forward with PRs #3954 & #3766 then?

[ocket8888]

I don't think so. Making changes in Go is easier than in Perl, so if somebody wants to spend the time writing it and someone else wants to spend the time reviewing it, a rewrite of a deprecated endpoint could still be valuable. It lets Perl die faster. Worst case scenario, we've wasted some time, but the impact on the project is neutral - not strictly negative.

[asf-ci]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/trafficcontrol-PR/4751/

[asf-ci]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/trafficcontrol-PR/4831/

[mhoppa]

Once the typo is fixed this is rdy to go, docs looks good, deprecation notices return from the api calls

[mhoppa]

retest this please