De-couple starting a trace server with opening a trace.

[williamsyang-work]

We currently cannot start a trace server without opening a trace. My understanding is that we want to search available TraceServerContributors for one where the trace being attempted to open is already available.

It would be simpler to have the functionality of opening a trace and starting a trace-server de-coupled. The functionality of starting a trace-server without the need of a file path would be invaluble.

My understanding and suggested solution:

Instead of having one current route for starting a server:

1. Start Trace Server with mandatory file path

We could have three options:

1. Start Trace Server with optional file path, searching available TraceServerContributors for one with the trace open (previous implementation).
2. Start ANY trace server from ANY TraceServerContributor (if any)
3. Open a trace with a current and available TraceServerContributor.