jersey2-guice is defunct

[josephks]

dropwizard-guice depends on jersey2-guice, but jersey2-guice is defunct and bugs there won't be fixed.

[jhaber]

It appears that the jersey2-guice approach of making HK2 + Guice play nicely is also no longer necessary, as newer Jersey versions allow HK2 to be replaced entirely (via custom InjectionManagerFactory). I think the best approach going forward is to write a GuiceInjectionManagerFactory and use that to ditch HK2 and jersey2-guice.

This should probably live outside of this repo so that hopefully all the various dropwizard<->Guice integrations could leverage it. I've been planning to give it a try but haven't found the time yet