New targets for building files needed by adb sync

Create new phony build targets for sync_system, sync_vendor,
sync_product, sync_system_ext, sync_odm, sync_vendor_dlkm,
sync_odm_dlkm, and sync_system_dlkm.

These build just the files on the associated partion, (e.g.
/system_ext), but not the image file (e.g. system_ext.img). Like sync,
but just for a single partition.

Test: modify System UI, m sync_system_ext && adb sync && am restart
Change-Id: I5aa40d7018e029a57114681dd16db3f1e5651a63