Revert "Stop tracking .iml files."

This reverts commit 4a5820352bf41be0ea5e27a641c51124cf73e127.
Revert "Stop tracking .idea"

This reverts commit d075ff64f4a074da4afa67919a00efbe92c8cf7a.
Revert "Stop tracking .gradle/"

This reverts commit 416a3a8a15eff49169db40f587f15f4faa896d09.