extract-utils: Extract A/B OTA partitions in parallel

Before:
real	1m32.730s
user	1m20.466s
sys	0m11.764s

After:
real	1m10.794s
user	1m21.270s
sys	0m11.592s

Change-Id: Idd4bc94ccb00d4e80ba1aa2efb86f1f29c5667ae
1 file changed
tree: 83467fbb30882597a6911ab05946b96d14e59ca8
  1. templates/
  2. extract_utils.sh
  3. sdat2img.py
  4. sort-blobs-list.py