Setup common tuna extract-files/remove Google self-extractors

Since tuna devices are no longer maintained by AOSP there is
no need to have multiple locations and duplicate files. This
Will put all common files in vendor/samsung/tuna and device
specific ones in vendor/samsung/maguro.

Change-Id: If4fc5688c82da031993b49a6f74807f31df21a1d
maguro: remove duplicate overlay

Already defined in vendor/cm

Change-Id: I887a3051884b29ba9aaecb370e8ab6d5020165cf
tuna: commonize what we can (2/4)

Change-Id: I9b38185aea5b7ebe9abed55dcb5b42927e43c36b