Update README.markdown and remove extra README files

Two commits: One updates the README.markdown to conform with template and include information about the providers, features, and params available in the module. The other commit removes all the extra readmes.
This is just a note for me to check that this is really how bzr works, (I've never used it), but the below stuff is normally what we'd consider a "checkout" rather than a branch, but that may be what bzr calls it.