Periodically check for unapplied policies on QQs

[LoisSotoLopez]

Proposed Changes

As documented https://github.com/rabbitmq/rabbitmq-server/issues/7863 :

If a quorum queue is unavailable when a policy is changed it may never apply the resulting configuration command and thus be out of sync with the matching policy.

This PR provides a function in rabbit_quorum_queue.erl that checks whether the current Ra Machine configuration for a queue corresponds to the expected configuration to be in use based on defined policies. That function is called by each queue process on tick (handle_tick).

Types of Changes

• [x] Bug fix (non-breaking change which fixes issue #NNNN)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• [ ] Documentation improvements (corrections, new content, etc)
• [ ] Cosmetic change (whitespace, formatting, etc)
• [ ] Build system and/or CI

Checklist

• [x] I have read the CONTRIBUTING.md document
• [x] I have signed the CA (see https://cla.pivotal.io/sign/rabbitmq)
• [ ] I have added tests that prove my fix is effective or that my feature works
• [ ] All tests pass locally with my changes
• [ ] If relevant, I have added necessary documentation to https://github.com/rabbitmq/rabbitmq-website
• [ ] If relevant, I have added this change to the first version(s) in release-notes that I expect to introduce it

Further Comments

.