Make it possible to assign "grid classes" to regions

Make it possible to assign "grid classes" to regions

- Added a (so far) cumbersome UI to assign grid classes to regions
- Add the "col" class to all regions (inspired by gridpak)
- Move region names outside of the layouts, only store them with regions (canonical place for region info)
- Remove some breakpoint/grid related cruft
- Enhance region list API to give us the list by machine name; useful at many places now