Allow configuration of metrics.

[fstab]

Metrics require configuration. A good example is a timer metric, where users will want to configure the bucked boundaries of the underlying histogram. github.com/fstab/micrometer-config-example contains several examples of how to configure metrics in Micrometer.

In the Microprofile metrics call on 21 June 2022 there was consensus that the following three configuration approaches should be available in Microprofile:

• Annotation-based configuration
• Java API, e.g. using a builder pattern
• Configuration file, e.g. a properties file. This allows operations to change configuration of a deployment without the need for code changes and a new releases.

For examples of how Micrometer does this, see github.com/fstab/micrometer-config-example.

[donbourne]

@fstab , could you please add (inline) the key points from the repos you point to, just so this issue can stand on its own without being affected by potential future changes in the referred to repos?