Implement Topologies CRUD endpoints

[zrhoffman]

I'm submitting a ...

• new feature / enhancement request

Description

• In order to create topologies, we we need to implement the POST /topologies endpoint.
• In order to retrieve topologies, we we need to implement the GET /topologies endpoint.
• In order to update an existing topology, we need to implement the Implement `PUT
• In order to delete a topology, we need to implement the DELETE /topologies?name={{name}} endpoint.

Traffic Control components affected ...

• Documentation
• Traffic Control Client
• Traffic Ops

Acceptance Criteria

• The Topology struct exists for the top-level Topology object, which includes the nodes array

• The TopologyNode struct exists for objects in a Topology's nodes array

• POSTing to /topologies with the request body given in the Flexible Topologies blueprint returns the response body given in the Flexible Topologies blueprint.

• The endpoint stores a topology in the TO database.

• The endpoint is validated according to the constrains listed under "API constraints" in the Flexible Topologies blueprint

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• A GET request to to /topologies gives you a response similar to GET /topologies example in the Flexible Topologies blueprint.
• You can filter results using the name query parameter
• You can filter results using the last_updated query parameter

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• A PUT request to /topologies?name={{name}} with the request body given in the Flexible Topologies blueprint example returns a response whose body matches the response JSON given in the blueprint.
• If valid, the changes to the topology are persisted to the database
• The changes are validated according to the constrains listed under "API constraints" in the Flexible Topologies blueprint

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• A DELETE request to /topologies?name={{name}} returns the response JSON given in the Flexible Topologies blueprint.
• The topology is removed from the database.

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• This routes are documented in the Traffic Ops API documentation:
  • The documentation includes an example request and response for each endpoint
  • The documentation includes descriptions of all request and response fields for each endpoint
• The routes is added to all Traffic Ops clients:
  • Traffic Ops Python client
  • Traffic Ops Java client
  • Traffic Ops Go client library
• API tests
• Unit tests
• The routes adhere to the API Guidelines blueprint.

See the Flexible Topologies PR for specifics: #4537