Add opentelemetry instrumentation

[cbrewster]

Why

Supercedes #110, we want to punt desingin interceptors until later.

We'd like to have tracing between client and server, this implements spans for the client side.

What changed

• Add tracing spans for each procedure call
• Add support for propagating the tracing context to the river server using the tracing field of the transport message
  • Ideally the trasnsport message wouldn't hardcode the tracing fields, but we'd need to fix that in the JS implementation

Test plan

• Connect this up to our internal usage, we should see spans for river procedure calls

[cbrewster]

Current dependencies on/for this PR:

• main:
  • PR Add opentelemetry instrumentation #115 👈

This comment was autogenerated by Freephite.

[blast-hardcheese]

One question, other than that 📈