Switch to proper PolicyKit implementation to avoid needing to ask for a password

Right now, the user is prompted for a password during pairing. This is required because Pairing tool doesn't work without write access /dev/hidrawX, which is not world-writable. This works, but it isn't ideal in the event that a user unplugs their keyboard receiver and thus can't pair the devices. Instead of this, we should switch to using a proper PolKit-1 implementation and set it such that a password is not required to pair the device.