Change container port to match metrics-bind-address

[kovaxur]

The 'metrics' container port is now set to 60000, but the default value for the operator's metric endpoint is 8080:

  -metrics-bind-address string
        The address the metric endpoint binds to. (default ":8080")

Without changing to 8080, it is impossible to monitor the operator via Prometheus.

This could be further refined to allow the user to set a custom port for monitoring, but I think this is not important now.

[it-percona-cla]

All committers have signed the CLA.

[hors]

@kovaxur please sign CLA

[kovaxur]

@hors done, thanks

[egegunes]

@kovaxur thank you for your contribution. there is another PR (#173) which implements the same things and additionally configures probes so we'll merge than one. I'm closing this one.