Ability to disable hardware keys via navigation bar settings (1/2)

Signed-off-by: Fusion-Rom <dragon7780@hotmail.nl>
[1/2]Add changes to allow hardware keys enable/disable through overlay

- Check devices related
  overlay/frameworks/base/core/res/res/values/fusion_config.xml
  to enable or disable

Signed-off-by: Fusion-Rom <dragon7780@hotmail.nl>
Added ability to disable the app switch hardware key[1/2]

Used by some devices like the Samsung Galaxy S5

Signed-off-by: Fusion-Rom <dragon7780@hotmail.nl>