[WM] reorganize JDK & clojure-api builds

We aren't really using the clojure-api build anymore, so I moved
clojure-api-build to clojure-api (it's a superset, so it shouldn't break
anything; it just installs leiningen). I also based it on the new
oracle-jdk-7-supervisor base image (see below).

I renamed oracle-jdk-7 to oracle-jdk-7-supervisor and based it on the new
supervisor container (since we're trying to remove that from the base
container). We need both Java and supervisor in the synapse-using containers, so
the options are 1. create a new base container w/ both or 2. install one of
them in every downstream container that needs both. I've opted for #1.