Revert "Remove remaining Google apps files"

This reverts commit 91bf6fa062b9523535d0e80cce00760901629d5a.
Revert "Revert "Add minimal Gapps (Play Store + Google Account support)""

This reverts commit 162683d481a232be79a9eca999261c8e4a609ad4.
Revert "Revert "Fix apkcerts for Google apps""

This reverts commit f9360a8835f47cd0223908f1527dc67205757160.