Fix quorum queues rejecting messages during deletion

[luos]

Hi,

Here is a proposal for the fix of #15334 as discussed.

Let me know what you think.

Proposed Changes

• implement a method to clear bindings before a queue is deleted
• leave the "after delete" procedure to make sure to clean up after deletion in case new bindings were created
• clear the bindings before the ra:delete_cluster call
• usage of default exchange may result in rejections

Fixes: #15334

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Types of Changes

• Bug fix (non-breaking change which fixes issue Quorum queue rejects messages during deletion #15334)
• 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

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[michaelklishin]

As seen numerous times before, we are "fixing" RabbitMQ while what needs fixing is a system design that depends on messages being accepted by a queue that's being concurrently deleted.

Deleting bindings before the queue is deleted doesn't make any more sense than deleting the queue first. The fact that it happens to "fix" a system that depends on a very subtle, inherently timing-sensitive behavior that differs between CQs and QQs doesn't justify the change.