Include client identity in OTel traces

If a client isn't emitting telemetry, the traces from the device server will show a call, but we won't know where it came from. Tango knows the client identity, so include this in device traces, when available.

New span attributes:

• tango.client_ident.location (The client_ip field)
• tango.client_ident.pid
• tango.client_ident.lang
• tango.client_ident.java_main_class
• tango.client_ident.java_ident

The client_ip field can be quite a range of things:

• giop:tcp:127.0.0.1:59938
• giop:unix:/tmp/omni-user/000064413-1747007653
• giop:tcp:[2001:2013:2e1a:a200:80a:e436:a21c:01e9]:59190
• collocated client (c++ to c++ call)

Notes:

• Individual fields are put into span attributes to simplify searching.
• We extract the PID from Java class info.
• The Java UUID fields are not included, as they aren't that useful. The string format of client_ident already omits this information.
• The get_client_ident method can crash if called from a non-omnithread. We check this, and also update DeviceTestContext to use an omnithread.
• Related to the previous point, the identity information isn't available in user handlers for Asyncio and Gevent green mode device servers - test updated to check this. However, the telemetry trace wrapper is called before adding the call to the event loop, so it can record this information.
• Fixed old API calls in prototyping.py.

A better place to do this is in cppTango, so once it is implemented there we can remove it from PyTango.