TO /api/x/steering output should be sorted

[rawlinp]

I'm submitting a ...

• bug report

Traffic Control components affected ...

• Traffic Ops
• Traffic Router

Current behavior:

Currently, the output of /api/x/steering is unsorted. This causes the response to be different each time it's requested, which causes TR to reload the steering data even though the steering data has not actually changed. This leads to a lot of unnecessary/misleading log output in TR.

Expected behavior:

Responses from /api/x/steering should be sorted by xml_id so that they only change if the actual steering data has changed.

Minimal reproduction of the problem with instructions:

Request /api/3.0/steering multiple times. Observe that the ordering changes with each request.