[1/2] Slims Hardware Key Rebinding

First thanks to CM team for the 2 years where we used their approach for our
custom hw key rebinding. This hardware key rebinding
patches did in the past a good job and we extended it prior 4.3 with a lot
Slim custom stuff.

But it is time to go new way and to do the complete
hardware key rebinding more flexible and more centralized. Especially due
that we have now all possible shortcut actions centralized in 4.4

Possible mapping are:
ACTION_HOME
ACTION_BACK
ACTION_SEARCH (in app search)
ACTION_VOICE_SEARCH
ACTION_MENU_BIG
ACTION_POWER
ACTION_NOTIFICATIONS
ACTION_QS
ACTION_RECENTS
ACTION_SCREENSHOT
ACTION_IME
ACTION_LAST_APP
ACTION_KILL
ACTION_ASSIST
ACTION_VIB
ACTION_SILENT
ACTION_VIB_SILENT
ACTION_POWER_MENU
ACTION_TORCH
ACTION_EXPANDED_DESKTOP
ACTION_THEME_SWITCH

and custom app/shortcut of course

Possible actions on all keys are:
normal tap / longpress / double tap

So to summarize if it is in settings array enabled user can bind whatever of the above
actions to every hardware key action.

Main changes to prior solutions are:
- do not depend anymore on hardcoded integer values. We use now strings. This has
  the advantage that we can save whatever shorcut or intent URI we have into this
  value. And gives us the possibility in future without changing anything on the hw
  key rebinding code to get more options/or modify the options. Actions are holded
  like on all other of our features in ButtonsConstants.java
- All actions are peformed over our SlimActions like all other features. SlimActions
  takes care about all possible solutions the user can run into and sets the right
  open animation, keyguard handling etc etc. As well it is easier to maintain only
  one code base.
- Only observe and update the values on hardware key devices. On non hw key devices
  the complete code is non operational
- Removed in settings the not needed overlay due that we can use the fb one to
  check if it is a hw key device or not.
- Major cleanup of a lot old code.

This patch add as well one new SlimActions action....VOICE_SEARCH

To configure your device you need to add the device overlay as usual:

overlay/frameworks/base/core/res/res/values/config.xml
<!-- Hardware "softkeys" present on the device, stored as a bit field.
         This integer should equal the sum of the corresponding value for each
         of the following keys present:
            1 - Home
            2 - Back
            4 - Menu
            8 - Assistant (search)
           16 - App switch
        For example, a device with Home, Back and Menu keys would set this
        config to 7. -->
    <integer name="config_deviceHardwareKeys">7</integer>

Also requires CarbonFibers commit (https://review.carbonrom.org/#/c/501/)
and overlay to function correctly

cheers HCP and kufi

https://github.com/SlimRoms/frameworks_base/commit/2cfd9aa74fe0fc7bc388ce01bc243bbf6ec06790
Change-Id: I25641f3d41232ccb81c0e57c2bfca9131a57df82