Add rake tasks to resolve dependencies, build RPMs and generate docs

See [BUILD.md](https://github.com/markllama/origin-server/blob/features/build/rake_tasks/BUILD.md) at the root of this branch for explanation and documentation

As a developer I would like to be able to build, test and document the OpenShift Origin server source code using only tools which reside within the source tree.

This patch adds a set of template Rake tasks and Rakefiles to the source tree to introduce several standard _rake_ tasks to prepare, build and generate documentation for the packages contained in the source tree.  When executed from the root of the source tree these tasks will walk the source code tree and execute for each package.

This patch includes documentation for the new tasks, including how to prepare, run and extend them.