[arch-releng] [RFCv2] Add cmd params to build.sh and other things.

Take care that this break current releng script, should be adapted to newer commands. ./build.sh all_iso_single -> ./build.sh build single all ./build.sh all_iso_dual -> ./build.sh build dual all ./build.sh clear_dual -> ./build.sh clear dual ./build.sh purge_single -> ./build.sh purge single etc... Also iso images are now placed in "out" directory by default (without -o) instead of "." Tested build and boot all is working fine.