Extract Jaeger-related code into shared library

[yurishkuro]

Is your feature request related to a problem? Please describe.

Both OTEL Collector and Jaeger want to import some pieces of each other's code, which doesn't work well.

• OTEL Collector wants to support existing Jaeger SDKs by accepting Jaeger data formats
• Jaeger backend wants to support OTLP format from OTEL SDKs

Describe the solution you'd like
Move Jaeger model related code into a shared library in jaegertracing org, including:

• UDP/thrift receivers from Jaeger
• OTLP -> Jaeger translators from OTEL collector
  The intention is that the new library would have only dependency on the data models, not other pieces of each project, e.g. Collector APIs for receivers / exporters won't be in the library and will have some adapters in the Collector code.

Describe alternatives you've considered
Currently OTEL Collector imports Jaeger backend code. Jaeger tried importing Collector code, but that leads to circular imports and is very difficult to manage.

Any open questions?
I'd like to hear thoughts from Collector maintainers since I am not deeply familiar with Collector code base.

[tigrannajaryan]

I think this is a good idea and should be doable once #3104 is done.

/cc @bogdandrutu another reason why extracting pdata is a good idea :-)

[bogdandrutu]

Done. Libraries are in contrib, @yurishkuro now the problem is the "jaeger/model" that we depend on :) jaegertracing/jaeger#3217