Change assembly targets to produce an executable.
Change assembly targets to produce an executable.

The `minimal` and `bundle` assembly configurations currently produce a .jar
file including all required dependency classfiles and resources.

Now an executable file is produced in the form linkerd-0.0.10-exec.

pawelprazak/linkerd,hhtpcd/linkerd,denverwilliams/linkerd,hhtpcd/linkerd,hhtpcd/linkerd,linkerd/linkerd,pawelprazak/linkerd,linkerd/linkerd,linkerd/linkerd,denverwilliams/linkerd,denverwilliams/linkerd,denverwilliams/linkerd,BuoyantIO/linkerd,BuoyantIO/linkerd,pawelprazak/linkerd