Convert packages/overlays/*/Android.mk files to Android.bp

See build/soong/README.md for more information.
Note: missing `product_specific: true` has been added to all the
module definitions in packages/overlays/Navigation*/Android.bp
to prevent overlay APKs from being wrongly placed in system/overlay.

Bug: 122332340
Test: treehugger
Change-Id: I7b64d0cfafb558bb1cbf6e3ca1d5cd4fc2a4d879