Track query derivation using Micrometer

[gregturn]

Observability is currently being adopted to handle metrics and tracing during "active" flows, such as invoking repositories, etc. This is handled by a current suite of Observation handlers and Zipkin-based integration tests.

The story regarding "startup" like query derivation will involve a different suite of integration tests, etc., and can wait until the first set of "active" flows is completed.

[mp911de]

On a related note, it would also be neat to track metrics for the mapping context initialization (AbstractMappingContext.afterPropertiesSet) to let users know how long the mapping metadata introspection takes for all initial entities.