getCall: add attempt, answer and termination timestamps along with other missing fields

Why is there a discrepancy between the fields available at GetCall endpoint and from the RecentCalls endpoint?

Fields available in RecentCall but not in GetCall,
- attempted_at
- answered_at
- terminated_at
- termination_reason

Similarly there are some fields that are available in GetCall but not in RecentCall. My system fetches the call data from Jambonz periodically and we have to call both the APIs to get all the fields. It would be nice to have all the fields available in both

Compare the GetCall and RecentCalls endpoint implementations, starting with how each endpoint assembles its response fields. Check existing API tests for both endpoints; done means both expose attempted_at, answered_at, terminated_at, termination_reason, and the other endpoint-specific fields consistently.

Written by the indexing model from the issue text.