lineage: Move all system props to PRODUCT_GENERIC_PROPERTIES

For Treble enabled devices, PRODUCT_PROPERTY_OVERRIDES puts props
added with that in /vendor/build.prop. While that's great for
device-specific properties, these are global Lineage properties
which are descriptive of the system side, so move them to the list
that gets populated into /system/build.prop.

Change-Id: I8bb3d0fe13188478d4f7dedc306740a40f44a3e8