Add XMPP Interop Test framework to CI pipeline

[guusdk]

Hello MongooseIM team,

I’d like to suggest integrating the XMPP Interop Test framework into the CI pipeline. This would help ensure standards compliance and detect interoperability issues. The framework supports both GitHub Workflows and CircleCI, which MongooseIM already uses, so integration should be straightforward as long as a running XMPP service can be made available in the pipeline.

There are already similar integrations for ejabberd and Openfire that could serve as references. I’d be happy to help work on setting this up, though I would need some guidance from the team.

Thanks for considering this!