This has no real impact on performance[1] but should
make it clear which application can run the broker
and/or publish to Hex.pm. In particular, applications
that we can't run the broker from will now give up
early if we try to.
Note that while the broker can't normally run from the
amqp_client application's directory, it can run from
tests and some of the tests start the broker.
[1] on my machine
* make amqp10_common dialyze green in make
* make rabbitmq_ct_client_helpers dialyze green with make
* fixup rabbitmq_prelaunch path ref
* Cleanup unused dep_* vars
* Fixup xref for rabbitmq_ct_helpers
I could not figure out how to make xref aware of the cli code without
also checking the cli code as well, and reporting additional errors
* remove unused file
* fix make diaylze for rabbitmq_stream_common
* update deps/oauth2_client/Makefile to match Bazel