Update `JerseyManagementContextConfiguration` so that customizer beans
are not longer applied. The endpoint resource endpoints are now added
with a registrar bean `@PostConstruct` method.

Prior to this commit, when running the management server on a different
port a `Resource` added by a customizer could be added two different
`ResourceConfig` instance. This breaks the singleton contract expected
by Jersey.

Fixes gh-17801
Co-authored-by: Phillip Webb <pwebb@pivotal.io>