Refactor several areas of the actuator endpoint code in order to make
future extensions easier. The primary goal is to introduce the concept
of an `ExposableEndpoint` that has technology specific subclasses and
can carry additional data for filters to use. Many other changes have
been made along the way including:
* A new EndpointSupplier interface that allows cleaner separation of
supplying vs discovering endpoints. This allows cleaner class names
and allows for better auto-configuration since a user can choose to
provide their own supplier entirely.
* A `DiscoveredEndpoint` interface that allows the `EndpointFilter`
to be greatly simplified. A filter now doesn't need to know about
discovery concerns unless absolutely necessary.
* Improved naming and package structure. Many technology specific
concerns are now grouped in a better way. Related concerns are
co-located and concepts from one area no longer leakage into another.
* Simplified `HandlerMapping` implementations. Many common concerns have
been pulled up helping to create simpler subclasses.
* Simplified JMX adapters. Many of the intermediary `Info` classes have
been removed. The `DiscoveredJmxOperation` is now responsible for
mapping methods to operations.
* A specific @`HealthEndpointCloudFoundryExtension` for Cloud Foundry.
The extension logic used to create a "full" health endpoint extension
has been made explicit.
Fixes gh-11428
Fixes gh-11581
1d39feffea