Since the `SampleJerseyApplication` class is already passed in the
`SpringApplicationBuilder` constructor, there is no need to override the
configure method of the `SpringBootServletInitializer` class.
Closes gh-5773
Jersey 2 has some Spring support built in but it's a bit awkward to
use in a Boot app, so autoconfiguration seems appropriate. The tests
and sample show how to use it, but the short story is that any
@Component can define JAX-RS endpoints via @GET etc.
There's a sample for Jersey 1 as well (pay careful attention to
the plugin configuration if you want to build an executable jar)
Fixes gh-1651
