Run Selenium suites against a cluster of nodes (backport #12165)

[mergify]

Proposed Changes

Run selenium tests against a rabbitmq cluster deployed via docker-compose. When the cluster profile is active or present, once the cluster is up and running, the test suite is run against each node in the cluster before stopping the cluster.
The other two execution modes run the test suites against a standalone docker instance of RabbitMQ activated via the profile docker or against a rabbitmq server run via make run-broker.

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes issue #NNNN)
• 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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This is an automatic backport of pull request #12165 done by [Mergify](https://mergify.com).