Introduces a new zephyr.FlashArea class that uses the zephyr flash map
api to implement the uos.AbstractBlockDev protocol. The flash driver is
enabled on the frdm_k64f board, reel_board, and rv32m1_vega_ri5cy board.
The standard and extended block device protocols are both supported,
therefore this class can be used with file systems like littlefs which
require the extended interface.
Maureen Helm