Adjust cachegroup parentage and deliveryservice-server assignment endpoints for Topologies

[zrhoffman]

I'm submitting a ...

• new feature / enhancement request

Description

API endpoints that are affected by cachegroup parentage or deliveryservice-server assignment need to be updated to take Topology-based Delivery Service assignment and parentage into account.

Traffic Control components affected ...

• Documentation
• Traffic Ops

Acceptance Criteria

• Assign a Delivery Service to a server (or vice versa). It should be prohibited to assign an EDGE server to a Delivery Service (or vice versa) that has a Topology assigned already.
• perform an operation on "child" cachegroups -- like queueing updates on "child" caches when changing the status of a "parent" cache. Child caches via both Topologies and legacy Cachegroup parentage would all need to be updated in that case.The line

See the Flexible Topologies PR for specifics: #4537

[rawlinp]

@zrhoffman this is pretty much done, right? Can this be closed?

[zrhoffman]

Yep looks done!