Question/Feature Request - V3 API to query all apps running on a diego cell

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Issue

Provide a query interface (preferably as a filter to GET /v3/apps to get list of apps given a IP address of a diego cell.

Context

As an operator we come across situations when a diego cell is running hot (high CPU), and we would like to see what apps are running on that cell. Currently we use a multi prong process

1. cfdot cell-state can be used to get the app GUIDs
2. query CAPI for the app names for each of the GUID

Another use case is our APM reporting a hot AI, and we would like to see if there are any other apps getting impacted. That involves

1. Query process/stats for the app being reported
2. get the host IP
3. use the two step approach above.

If we can query the CAPI directly to get list of apps running on a given host (by IP or Bosh DNS Name)it will make operator lives bit easier. If there is an easier approach to the problem statement I can explore that too.

Start with the V3 GET /v3/apps endpoint and compare it with the cfdot cell-state and process/stats workflows described in the issue. Define how a host IP or BOSH DNS name should identify apps and what the response should contain; done means operators can query CAPI directly for all apps running on that host.