Move bsp-specific configuration out of build/

- Moves lots of board specific stuff out of this repo. That includes
stuff like bootloader building, recovery images, sdcard (if a platform
supports it), and board-specific pbuilder targets.
- Also notably, this allows pbuilder output to end up in different
directories, to help mirror our apt repository configuration: after this
change, packages will either end up in packages/core or packages/bsp.

Change-Id: I11d137f8ba8d71ef3e14afa325d79be06d8ded0e
8 files changed