Give dht and coordinator their own telemetry instances

[iand]

Decouple dht and coordinator metrics so we separate responsibilities cleanly. Both components will use the same meter and tracer providers by default.

This also removes the error return from DefaultCoordinatorConfig() which was only needed because it was initializing a Telemetry struct with metrics that it does not touch.

[dennis-tra]

That error return value bugged me as well! Thanks for removing it!

[iand]

@dennis-tra happy for me to merge this?