Add ServiceMonitor to Operator startup

[secondsun]

The operator should be able to detect if we have metrics installed and set those up at startup.

See https://github.com/aerogear/unifiedpush-operator/blob/537c01dbf073f8455969cf52c413934dbe867906/cmd/manager/main.go#L173 for an example.

TODO :
[ ] : Decife metrics will we capture
[ ] : Define how we will interact with service manager

[wtrocki]

We have access to operator logs and monitoring on sandbox environments.