create a target for utilities
ota: Fix inclusion of the backup script
Allow override of device asserts, including multi-device support.

Set in board file with TARGET_OTA_ASSERT_DEVICE.
(cherry-picked from commit 0f452f21fc9323b9d1fe746161761cf40aaa5030)

Change-Id: I3d06bdc0e3e26bde0c0e646accd050364f9713b9
build: Run squisher for the bacon target

Change-Id: If33402a5eb1661345c7d37ec1778742096449c70
TARGET_CUSTOM_RELEASETOOL is a squisher replacement

Change-Id: I9c7126d6bbe0303c1d35bb54ec2f0c9187b131e0