Fix parent.config generation for MSO with required capabilities

[rawlinp]

What does this PR (Pull Request) do?

Server capabilities do not apply to ORG servers (origins), so don't
check for them.

Which Traffic Control components are affected by this PR?

• Traffic Ops ORT

What is the best way to verify this PR?

Create an MSO delivery service (multiSiteOrigin: true) and a required capability. Assign 2 ORG servers and at least 1 EDGE server to the delivery service. The EDGE server must have the required capability. Make sure at least 1 MID in the CDN also has the required capability. On that MID, run ORT and verify that the line in parent.config for this delivery service contains the 2 ORG servers.

Next, create a topology with your edge -> mid -> origin cachegroups, and assign it to your MSO delivery service. On the same MID as before, run ORT and verify that the line in parent.config for this delivery service contains the 2 ORG servers.

If this is a bug fix, what versions of Traffic Control are affected?

• master
• 5.0.x
• 4.x

The following criteria are ALL met by this PR

• This PR includes tests
• bugfix, no docs necessary
• This PR includes an update to CHANGELOG.md
• This PR includes any and all required license headers
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

[ocket8888]

re-running ciab check

[zrhoffman]

• TestMakeParentDotConfigTopologiesMSOWithCapabilities and TestMakeParentDotConfigMSOWithCapabilities fail without the fixes included in parentdotconfig.go (but pass with fixes included)

• Without the patch:

  • A MSO DS whose origin servers do not satisfy its required capabilities yields an empty parent.config (other than the # DO NOT EDIT comment) for servers in the child cachegroup of the ORG_LOC cachegroup.
  • parent.config is successfully populated if the origin servers do satisfy the DS's required capabilities (by inserting server server capabilities directly into the DB).
  • This is the case for topology-based and non-topology-based delivery services.

• With the patch, the parent.config has a dest_domain= line that includes the origin servers assigned to the MSO DS, for both topology-based and non-topology-based DSes.

The tests include redundant types, but that is a code style choice and is fine because it is more explicit that way.