Proposal to consolidate instrumentation directories a bit

[trask]

Organize the instrumentation directories a bit, consolidating under top-level library/frameworks where possible, e.g.

• move akka-actor-2.5, akka-actor-fork-join-2.5 and akka-http-10.0 under common akka directory
• move dropwizard-testing and dropwizard-views-0.7 under common dropwizard directory
• move jaxrs and jaxrs-client under common jaxrs directory
  • should existing jaxrs modules be renamed jaxrs-server or jaxrs-container or ...??? (leaving them as jaxrs is an option also)
• move jetty and jetty-httpclient under common jetty directory
  • and rename existing jetty modules to jetty-server
• move kafka-clients and kafka-streams-0.11 under common kafka directory
• move play and play-ws under common play directory
  • and rename existing play modules to play-mvc
• move reactor-3.1 and reactor-netty under common reactor directory
  • and rename existing reactor-3.1 to reactor-core-3.1
• move vertx-http-client, vertx-reactive-3.5 and vertx-web-3.0 under common vertx directory

EDIT crossing off items above that were done in #4965

[trask]

Closing, I think this is good enough at this point