Notification LED Control (2/2).

* Make led color customizable.
* Global and per-app settings.
* Default led color is white.
* The option category replace old stock on/off checkbox.
* Remove useless code from display settings, the feature has its own java files.
* The java files in settings are stored into its own com/android/settings/notificationligh folder.
* Credits into code comments of each specific java file.

PS2:

* Use already defined string.
* Fix conflict after a previous commit merge on gerrit that wasn't linked.

PS3:

* Add other strings.
* Fix icon call.

PS4:

* More aosp style led category string.

PS5/6:

* Update Description.
* Add missing header in pa_arrays.

PS7:

* Fix variables check in notification light.
* Expose battery led indicator control in LED settings.
* Update strings and add battery category one.

PS8:

* Ditch battery led option, remove related code and classes.
* Add a boolean to check if device has led.
* Update commit description.

PS9/10:

* Fix getResources().
* Update description.

PS11:

* Fix strings confilcts after app ops merge.
* Remove battery strings.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>

Change-Id: I7ca73f9cf4631d44fa3020b079a8c9e84b666f41
Rework notification LED a bit.

* Clean up code, improve logic.

PS6: According to android writing style update string for "OK"
     https://developer.android.com/design/style/writing.html
PS7: Whitespaces.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>
Change-Id: I5408d895b52255a8352ebe8ea1a79be92af9c1a1