Remove errors logs at shutdown

[mbusi]

To remove annoying error logs at shutdown we added a Amqpx.DirectConsumer module to implement the :amqp_gen_consumer behaviour reusing (through defdelegate) all :amqp_direct_consumer code except for the handle_info function where we added two pattern matches to handle the :shutdown exit reasons as normal, expected occurrences.
We tested the solution running the test/gen_test.exs suite and those pesky error logs disappeared; being certain of anything is quite hard with this lib though cause tests, in general, are pretty flaky.
We may want to test the implementation in a non critical project of ours before creating a new release

[francescopellegrini]

🚀

[succoDiPompelmo]

Deployed the branch on Pradesh and seems to be working fine in production. I also did kill some pods in staging and no errors show up in the logs anymore.