change server primary key to only id

[mattjackson220]

What does this PR (Pull Request) do?

• This PR fixes Fix Traffic Ops Server Primary key to be ID #4941

This PR updates the server table so that only the id is the primary key instead of the id, cachegroup, type, status, and profile

Which Traffic Control components are affected by this PR?

• Traffic Ops

What is the best way to verify this PR?

verify that all unit and API tests are successful, verify that adding, editing, and deleting a server works as before except that servers cannot have the same id twice

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

The following criteria are ALL met by this PR

There are no test updates because it is covered by existing tests
There are no CHANGELOG updates since it is not a functionality change
There are no doc updates since it is just a db change

• I have explained why tests are unnecessary
• I have explained why documentation is unnecessary
• An update to CHANGELOG.md is not necessary
• This PR includes any and all required license headers
• This PR ensures that database migration sequence is correct
• This PR DOES NOT FIX A SERIOUS SECURITY VULNERABILITY (see the Apache Software Foundation's security guidelines for details)

Additional Information

[rimashah25]

Manual tested (successful) as follows:

1. Ran a POST /api/3.0/servers to create a new server. Returned 200 response
2. Got the ID (eg 15) from the newly created server.
3. Created another server with the ID (eg 15) received from step 2.
4. Got the following error with a 400 response.
   {"alerts":[{"text":"server with id 15 already exists. Please do not provide an id.","level":"error"}]}
5. I deleted the existing server (ID:15)
6. Ran a POST call (/api/3.0/servers) with the same ID (15) and was able to create a new server.

Unit tests pass
API tests pass (v2/v3)
Code is formatted correctly
LGTM