Implement AMQP Message client for Job updates

[psiemens]

This issue was originally opened here by @davidhouseholter-hah on August 20, 2021: https://github.com/onflow/wallet-api/issues/17

I added a new package to publish messages to a message queue. I still need to add the event bus name to the cfg file but I thought it was best to talk to members of the team about architecture. I would like this logic to use the JobService but currently, the service is not being used for creating or update.

The changes I have made currently: https://github.com/onflow/wallet-api/compare/main...davidhouseholter-hah:ampq_message_client?expand=1

[psiemens]

@latenssi @nanuuki @tehranifar Do you have any input on the architecture here?

[nvdtf]

My quick feedback:

• There needs to be a layer of abstraction between the job service and AMQP package, because we might need to support other message queues in the future, like Kafka.
• Some functions like UpdateJob might need to be renamed to better accommodate the new "store or publish" logic. Going a step further I don't think publishing should be done in the database layer, so a rewrite is needed.
• Needs unit tests + docker compose integration with a sample AMQP service for local development.
• The new env variables need to be renamed to specify AMQP in their names.
• AMQP publish should be disabled by default and only in use when configured.
• Seems to me there are a lot of config variables in the AMQP service. We might need to expose some of them in the env config.

[sheerryy]

AMQP Message client for Job updates is very hand. Can you guys give any ETA for this feature? Thanks!