Make opentelemetry-javaagent "all" artifact the default artifact

[trask]

And introduce a "slim" artifact that has no exporters (same as what is now the default artifact).

Some notes from Aug 12 SIG meeting:

• The “-all” jar will be confusing once we move some of the instrumentation to contrib
  • Then it will not really be “all” (will likely have a separate javaagent released from contrib that has everything, similar to otel collector)
• The “-all” jar has already been a source of confusion
• For a while the default had exporters anyways

and see #3900 (comment)

[trask]

Adding notes from discussion in September 21 SIG meeting:

Original thinking was that opentelemetry-javaagent-contrib.jar would be the everything jar after splitting out half+ of the instrumentations in this repo to contrib (e.g. initial thought on split is based on this).

But now thinking is that, given one of the drivers of the javaagent is deployment simplicity and supportability, it's may be better to promote just a single "everything included" opentelemetry-javaagent.jar that has all the instrumentations. (plus an opentelemetry-javaagent-slim.jar that has all the instrumentations + only the slim otlp/http exporter, which is ~8mb compared to with all exporters ~25mb)

If we decide this is the way forward, then it's ok to go ahead and make this rename now and start publishing opentelemetry-javaagent.jar with all instrumentations and opentelemetry-javaagent-slim.jar with all instrumentations + only the slim otlp/http exporter, since there wouldn't be a further break in naming when we split out half+ of the instrumentations from this repo to contrib.

[iNikem]

Still think that we need a name for "just agent" (maybe with internal instrumentations to guarantee that all extensions will actually work)

[trask]

Still think that we need a name for "just agent" (maybe with internal instrumentations to guarantee that all extensions will actually work)

can you itemize use case(s) for this "just agent"? maybe that will help us come up with a good name for it

[iNikem]

Still think that we need a name for "just agent" (maybe with internal instrumentations to guarantee that all extensions will actually work)

can you itemize use case(s) for this "just agent"? maybe that will help us come up with a good name for it

I just remembered my idea of its name: -core