This change also simplifies the entrypoint in the func.yaml, so only the
user's function is referenced. All runtime related stuff is completely
abstracted away from the user.
This is based on !34 in jfaas. The plan is to only depend on the api in
the pom file and for the runtime to be embedded into the run image.
Currently, there isn't a registry to push a Java image with the runtime
embedded so for run, we'll still reference both the api and runtime in
the pom.
