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
The main entry point is `make github-actions` which generates the
workflows.
Currently, it handles workflows to test the project with different
versions of Erlang.
Now that everything was moved to common_test, we don't need the old
framework anymore.
The only target still in use was `cluster-other-node`. As it was only
used by rabbitmq-java-client, the target was moved there.
The `test` target, which was an alias to `tests` (the regular Erlang.mk
target), was removed at the same time.
[#127356157]