TP: Allow users to assign ORG servers to topology-based DS

[zrhoffman]

I'm submitting a ...

• new feature / enhancement request

Traffic Control components affected ...

• Traffic Portal

Current behavior:

Traffic Portal prevents users from creating deliveryservice server assignments for topology-based delivery services.

New behavior:

To support Multi-Site Origin, ORG servers must always be directly assignable to a Delivery Service in Traffic Portal regardless of whether or not the Delivery Service employs a topology.

Minimal reproduction of the problem with instructions:

In Traffic Portal:

1. Create a topology
2. Create a delivery service with the topology
3. Create a server of type ORG
4. Try to assign the ORG server to the delivery service (as a deliveryservice server assignment)