Expose new metrics from fluent bit

Now we have updated to 1.8 (K8S-2296) we can make use of the new metrics options natively provided by fluent bit.

See: https://fluentbit.io/announcements/v1.8.1/

As part of this we should expose port 2021 as well by the operator along with a default configuration that exposes the metrics for people who want them.