Add prometheus endpoint to micrometer extension

Micrometer metrics are currently only available through an OTLP collector. While this is working fine, many IT infrastructure stacks are still using a Prometheus scape config for each instance.

Adding micrometer metrics as a Prometheus endpoint in the mgmt-interface (like the classic metrics) would be beneficial to many customers.

Afaik it was already the case in the Wildfly Preview 27 or so.

E.g. with a switch depending on the config:
https://github.com/wildfly/wildfly/blob/d8176e3fd44ab3e144b89eb975ea1ab75eaebb0b/observability/micrometer/src/main/java/org/wildfly/extension/micrometer/MicrometerRegistryService.java#L56