Support for Jaeger remote sampler

[almariah]

The remote sampler will consult Jaeger agent for the appropriate sampling strategy to use. This allows controlling the sampling strategies in the services from a central configuration in Jaeger backend, or even dynamically.

[jmacd]

@lizthegrey Do you have thoughts on this, given your OTEP about sampling?

[joe-elliott]

Since this is just a proxy in Jaeger does it make sense to configure and handle this entirely in the receiver?

If we can agree on how to handle this I would be glad to add the feature as we need it internally to start using the otel collector.

[bogdandrutu]

We discussed about the collector integration to use extensions.

[annanay25]

I will pick this up.

@bogdandrutu - should this issue be moved to otel-col repo?

[rghetia]

move to collector repo

[jmacd]

I suspect there is a desire to apply sampling in the client-side SDK, in which case this issue belongs here.

[annanay25]

Yes, once jaeger remote sampling is implemented in the agent/collector, we can pick up the client side SDK sampling.