Great refactoring of "Repository Manager"

- [x] Create a `RM` namespace for all the repo manager stuff
- [x] Move existing classes to own directory
- [x] Move `RepoMan` into `RM` namespace
- [x] Rename `RepositoryInfo` to `Repo` and move it to `RM` namespace
- [ ] Write cached abstraction layer for references

... and whatever I come across that way.