Allow users of self-contained builder to provide alternate location for assemble scripts

[mfojtik]

This is following the logic @bparees used for https://github.com/bparees/docker-image-examples/tree/remote_scripts/centos-wildfly-noscript

You can overide the default builder scripts by adding -s URL argument to the builder. In that case, builder image will fetch prepare,run,save-artifacts and restore-artifacts scripts from a remote HTTP directory and replace the original scripts.

$ docker run -v $(pwd):/tmp/src openshift/centos-ruby-builder -s http://URL/scripts

alternatively, users can place their customized scripts into .sti/ directory in the root of their GIT repository. The '-s' parameter takes precedense here.

[smarterclayton]

Is this ready to deliver?

[bparees]

pretty sure this is dead code since we moved the ruby builder to openshift/ruby-19-centos.

[smarterclayton]

Let's nuke this then - and remove the builder from docker index.