Add support for specifying a regex as a queue name matcher

Instead of having to specify a list of potentially changing queue names, you can specify a regex in rabbitmq.yaml and have the agent match against the regex
Do you know that you can run a check by running
```
sudo -u dd-agent dd-agent check rabbitmq
```
I know we add a `__main__` section sometimes to run it manually, but we shouldn't do that and duplicate this same piece of code everywhere...