Add metrics for AoP

[gaoran10]

Motivation

Currently, there are no metrics for AoP, it's hard to monitor AoP status. This PR will add metrics for AoP.

Modifications

Add below metrics for AoP.

MetricsLabel	Description	Labels
vhost_count	vhost count	cluster
exchange_count	exchange count	cluster, vhost
queue_count	queue count	cluster, vhost
amqp_connection_counter	amqp connection count	cluster, vhost
exchange_write_counter	exchange write count	cluster, vhost, exchange_name
exchange_write_failed_counter	exchange write failed count	cluster, vhost, exchange_name
exchange_read_counter	exchange read count	cluster, vhost, exchange_name
exchange_read_failed_counter	exchange read failed count	cluster, vhost, exchange_name
exchange_ack_counter	exchange ack count	cluster, vhost, exchange_name
exchange_route_counter	exchange route count	cluster, vhost, exchange_name
exchange_route_failed_counter	exchange route failed count	cluster, vhost, exchange_name
queue_write_counter	queue write count	cluster, vhost, queue_name
queue_write_failed_counter	queue write failed count	cluster, vhost, queue_name
queue_dispatch_counter	queue dispatch count	cluster, vhost, queue_name
queue_read_failed_counter	queue read failed count	cluster, vhost, queue_name
queue_ack_counter	queue ack count	cluster, vhost, queue_name

Verifying this change

• Make sure that the change passes the CI checks.

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (10MB)
• Extended integration test for recovery after broker failure

Does this pull request potentially affect one of the following parts:

If yes was chosen, please highlight the changes

• Dependencies (does it add or upgrade a dependency): (yes / no)
• The public API: (yes / no)
• The schema: (yes / no / don't know)
• The default values of configurations: (yes / no)
• The wire protocol: (yes / no)
• The rest endpoints: (yes / no)
• The admin cli options: (yes / no)
• Anything that affects deployment: (yes / no / don't know)

Documentation

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• no-need-doc

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• doc

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[github-actions]

@gaoran10:Thanks for your contribution. For this PR, do we need to update docs?
(The PR template contains info about doc, which helps others know more about the changes. Can you provide doc-related info in this and future PR descriptions? Thanks)

[github-actions]

@gaoran10:Thanks for providing doc info!

[ronfarkash]

Hey, bumping this. Metrics for AoP would be very useful for a lot of users!