Pull fullmte-common and fullmte-vars into a common dir so they can also
be used by other devices. See the topic changes for device/google/gs-common.
Bug: 288843255
Test: run soong for shiba_fullmte, build/flash husky_fullmte.
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:dc02c7176f592d00610ca5db3648f90194434c2d)
Merged-In: I6cc636596acff8b5234197fe26f85e27f7e85a62
Change-Id: I6cc636596acff8b5234197fe26f85e27f7e85a62
cherry-pick to udc-qpr-dev