Reland Support incremental dev option OTA during signing

This allows incremental dev option to be used on release-key devices.
Boot images are signed during the signing process, and hence the dev
option OTAs(which are derivative of boot image) need to be re-generated.
Previously we only re-generate full OTAs, now we support incrementals
too.

Previous land of the CL had a bug where AddDtbo() is called even for
devices which do not have a DTBO partition, causing signing failures.
This reland fixes the issue above by checking "has_dtbo" in
misc_info.txt

Test: th
Bug: 339658378

This reverts commit 29c7842c.

Change-Id: Ifb080aaa15faf752ab1cff687c54d00290c1bfa6