fb: add general torch support for our app

till now we used an settings overlay. At least all our devices
without torch do not compile the package at all. So check
if package exists if user eg want to setup shortcuts to
torch in settings. Due that our app is needed for torch
and the user will not delete it this is an acceptable way.

see @TorchConstants and @SlimActions

Change-Id: I208fb310fbd0596dd9956d6a2c7fe106859bb4d6
(cherry picked from commit a58f5848865b31949b44ac50679ef652706c922b)
(cherry picked from commit 194f1354348981f9059fc2c77b66fdad0bfafafb)
Add support for TorchConstants

(cherry picked from commit 8b05f3c9f38f9e4bf3e447ffe2ea0b27d56b93c1)