Include vhost limits and metadata in definitions exported from the management UI

[anhanhnguyen]

Proposed Changes

The change is to include vhost limits and metadata in definitions exported from the management UI.

Fix the issue reported at #10515.

Types of Changes

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• Bug fix (non-breaking change which fixes issue Definitions export from management UI does not include vhost metadata #10515)
• 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]

Thank you but this PR won't be accepted (in its current form, the end goal sounds reasonable to me).

There are several serious omissions or incorrect assumptions:

• You cannot just change the list of info keys willy-nilly, they usually exist for a reason
• You have missed rabbit_definitions where you arguably should have started, therefore rabbitmqctl export_definitions may or may not return the limits
• It does not add any tests to the definition import suites (both in core broker and in the management plugin)
• Therefore it remains an open question whether such exported definitions can be imported back

[michaelklishin]

Instead, limits should be exposed like so:

• Start with rabbit_definitions, the management plugin code paths should arguably be removed by now and just use rabbit_definitions
• definition_import_SUITE and its input cases should be covered first
• Then test rabbitmqctl export_definitions and its importing counterpart manually
• Test global definition import vs. single virtual host definition import
• Then move on to the HTTP API

In addition, HTTP API clients — and there multiple popular ones — may have to be updated as some of them (Go, Ruby, Hop, Rust) include definition operations one way or another.