common: fastboot: support sdfuse command

common: fastboot: support sdfuse command

This patch implements sdfuse command which is a variant version of
fastboot to use sdcard images. The sdfuse command consists of three simple
commands.

flashall: flash whole image files from the first ext4 partition of
sdcards
flash: flash a image file which is specified from command line
format: format eMMC partition to gpt partition

All commands use facilities of fastboot commands to implement easily.

Change-Id: I5eb316ee0f852fe7e74dacb7ff8c17eec7dd83ca
Signed-off-by: Chanho Park <chanho61.park@samsung.com>