RabbitMQ exporter implementation

[swar8080]

Description:
This is the completed implementation of the rabbitmq exporter.

Link to tracking Issue:
#28891

Testing:

• Unit tests
• Happy path with rabbitmq running locally and in the cloud, testing different configuration options
• Error cases
  • Fail to connect during start-up
  • Invalid credentials
  • Connection lost midway through publishing to the queue. The component attempts reconnecting on the next publish attempt
• Concurrent publishing, both with and without connection issues

Documentation:
Updated README with more configuration options

[swar8080]

FYI @atoulme this is ready for review (since you're the component sponsor)

[atoulme]

The code looks good but I didn't test it myself. This can land and we can add a test like this one to make sure no leaks are present in a subsequent PR: https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/zipkinreceiver/package_test.go

[evan-bradley]

@swar8080 Could you resolve the conflicts?

[swar8080]

@evan-bradley the pipeline passed if you want to merge