Revert "[aml] introduce guisettings overrides"

This reverts commit 13cd0b669fab4f8752eab7ab4524fc661766b20d.
[aml] introduce guisettings overrides v3

This is useful for packagers as they can override menu defaults in as.xml
rather than patching xbmc code.

Usage example:

  <hidesettings>
    <setting>lookandfeel.soundskin</setting>
    <setting>videoplayer.rendermethod</setting>
  </hidesettings>
Revert "[aml] fixed, force system volume to max so passthrough works"

This reverts commit e509e31fd3ddb43487bd5624eeb3b6992c809222.
[aml] fix audio issues with SoftAE, temp until Frodo 12.1 comes in