Refactor bundle.py for using OOP, args inspired by tar

- Removed concept of media-type from bundle.img
- bundle.py's args are more tar
- Files included are now based on descriptive and ordered resources file (see resources.yaml)
- bundle.py now also generates an enum suitable for inclusion in C/C++ to correlate with IDs
  - This means that media-type can be removed from FW source as well, as IDs can now be entirely managed by bundle.py
- Multiple resource files can be specified, allowing bitmaps, fonts and strings to be in separate files if desired