[CHANGE] added celery exporter to accept different queue name

[umaparvat]

This option will enable to monitor different versions of the queue in ZERO downtime deployment options( blue/green or canary deployment).

If celery is going with a different queue during deployment to avoid new task addition/deletion. People would choose different queue versions in the rolling updates.

Now celery exporters also can have a different queue as part of rolling updates or by default it would use the celery queue.

celery-exporters -q "celery"