Revert "Settings: Camera button rebinding and longpress camera lockscreen action (2/2)"

This reverts commit 97d51fa6deb54e20c959887f530789ab2f22119d.
Settings: Camera button rebinding and longpress lockscreen action additions (2/2)

Adds new config_deviceHardwareKeys bitmask for camera button.
Lets you rebind the camera press/longpress and adds a new KEYCODE_CAMERA handler to inject a longpress KeyEvent in order to let you bind keys to actually trigger the shutter, in addition to launching the app itself.

This also adds KEYCODE_ASSIST and KEYCODE_APP_SWITCH to the available keys to assign longpress lockscreen actions to.

Change-Id: Iad1c850e07974ef45313b32c9427b9e0d31dedd7