Settings: Navigation bar Quick launch shortcuts (1 of 2)

This allows up to 3 targets on the Navigation bar ring
or Home buttons with custom Quick launch shortcut actions.

Patchset 1 to 17 - Initial commits and edits
Patchset 18 - Update preference layout
            - Use AOSP terminology for the feature name
            - Group under new 'Navigation bar' category
            - Rename Navigationbar buttons configurator
Patchset 19 - Update commit message with x of y indicator

Change-Id: I91a7b86b7bfa79526b537e28b510ec078a58c956