initial popupmenu with switching functionality

Created the following:

• initial popupmenu for selecting a graphics and fan profile
• using the icons only or the fan profile as this is the one that gets displayed in the panel
• showing the current profile / gpu inside the popup menu with a colored background behind checkmark after the active entry
• using the icons from asusctl for the profile notifications, so no need to systemwide install the icons
  • this should then also be ok for releasing it on extensions.gnome.org

somethings could be more elegant but it's working and functionality is added

there is currently no modal dialog when switching gfx profiles - that should be added, too