[Settings] Refactor hw keys handling with navbar presence (2/2)

This commit removes per hw keys disabler/enabler. Now all hw keys get their functionality observing navbar state. Navbar on = all hw keys disabled and navbar off = all hw keys enabled. We now use key disabler hw support provided by CyanogenMod to totaly disable hw keys in devices supported by it. Since we have a navbar on/off option in all crDroid supported devices (because of Pie controls) and not all devices have key disabler support, crDroid also disable all hw keys in PhoneWindowManager.java if needed. Thanks CyanogenMod for a bunch of new classes used now provided by them!

Change-Id: I1b173d491758838babd61aaba781991be67160ab