[AmazonMQ] RabbitMQ - Add overview dashboard

[agithomas]

• Enhancement

Proposed commit message

Add overview dashboard for RabbitMQ in ActiveMQ

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.
• I have verified that any added dashboard complies with Kibana's Dashboard good practices

Author's Checklist

• Integration testing
• Verified that the ActiveMQ related broker / queue / topic details are not appearing in the dashboard

How to test this PR locally

• elastic-package build
• elastic-package stack up -v -d --services package-registry

Screenshots

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: fd59881

cc @agithomas

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
99.9% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube

[daniela-elastic]

A few points based on the 'Observability integrations dashboards best practices' guidelines:

1. Use hyphen "-" to separate complex widget names that are broken down by certain entity such as "by node", "by broker", etc.
2. Remove the word "count" or other similar synonyms where it seems redundant. For example, instead of "Queue count", replace with "Queues"; instead of "Total messages count", replace by "Total messages"; instead of "Messages ready count", replace with "Messages ready" or maybe even "Ready messages"; instead of "Consumer count", replace with "Consumers", and so on and so forth.
3. Name each section of the dashboard. The first section is unnamed (it contains resource utilization metrics and a melange of connections, consumers, messages and rates), in addition to two named sections for Node metrics and Queue metrics.