added a quarkus json logging for the registry app

[vsverchkov]

Added a quarkus json logging for the registry app for logs indexing into Elasticsearch/Opensearch

[apicurio-bot]

Thank you for creating a pull request!

Pinging @jsenko to respond or triage.

[vsverchkov]

I thought about adding a doc about new env for json logging, but didn't find the part with available env vars.
maybe create a doc with available env vars and their descriptions?

[EricWittmann]

Thanks @vsverchkov - we are going to be doing a major renovation of all our ENV variables for the upcoming 3.0 release (from main). That should include better documentation as well.

Your var name will likely change as part of that renovation, but what you've contributed here is great, thanks. :)