Bootloader for CAN

[vChavezB]

Hi @JPHutchins , just wanted to say thanks for the awesome job on this project.

As I mentioned before, I have integrated an unofficial CAN bootloader into Zephyr OS for a custom board.

Instead of developing my own bootloader, using mcuboot + smpmgr reduced the time needed to get this into production.

Keep up the good work 🚀