Adding Android verified boot 1.0 metadata into ENG builds

Adding verified boot metadata with a "disable magic". The resulting
metadata at the end of each image (e.g., system.img, vendor.img) will
be the same as triggering an "adb disable-verity" on an USERDEBUG image.

This can help simplify the code on fs_mgr, which won't have to check if
current image is an ENG build or not.

Bug: 63056044
Test: boot sailfish eng/userdebug builds
Change-Id: I95d23ac7b76c04d6d4483c9c4dc1de16bf0d9c3a