Setting AMQP custom images is not possible anymore

Summary

Beginning with release 0.20251127.0-rolling.T101903.g92875879628b, overriding the RabbitMQ by setting .spec.imageRef inside the AMQPServer manifest is not possible anymore.

Resolution

This feature is still required by some users. Since we need to configure multiple images due to the upgrade implementation, the user should be able to override all images of different versions with a different setting.

Proposal

Allow another setting .spec.imageOverrides inside the AMQPServer manifest where users can override each RabbitMQ version from the pinned versions. It must behave like the YAOOK_OP_VERSIONS_OVERRIDE in the operator, but on a per AMQPServer basis.

Specification

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this issue are to be interpreted in the spirit of RFC 2119, even though we're not technically doing protocol design.