Integrate MindTheGapps into AOSP

Edit .repo/manifests/default.xml

<remote name="MindTheGapps" fetch="https://gitlab.com/MindTheGapps/" />

<project path="vendor/gapps" name="vendor_gapps" remote="MindTheGapps" revision="sigma" />

Edit device/oneplus/lemonade/device.mk

include vendor/gapps/arm64/arm64-vendor.mk

Edit device/oneplus/lemonade/BoardConfig.mk

BUILD_BROKEN_ELF_PREBUILT_PRODUCT_COPY_FILES := true