build: build-script

set default -j level for repo sync to 4
removed pointless -j level from mka bacon
added an advanced setting to set custom SCHED_BATCH
cleaned up final build settings to be a bit more understandable

Change-Id: I23a5f1c5178cdba121263a336217e988ec2a648d
Merge "build: build-script" into kk_mkt