chore(EXAMPLES): add missing adaptive quality example scene
chore(EXAMPLES): add missing adaptive quality example scene

The Adaptive Quality example scene was missing from the examples list
so it has now been added.

red-horizon/VRTK,Blueteak/SteamVR_Unity_Toolkit,adamjweaver/VRTK,gpvigano/VRTK,TMaloteaux/SteamVR_Unity_Toolkit,virror/VRTK,thestonefox/SteamVR_Unity_Toolkit,gomez-addams/SteamVR_Unity_Toolkit,mattboy64/SteamVR_Unity_Toolkit,thestonefox/VRTK,nmccarty/htvr,gpvigano/SteamVR_Unity_Toolkit,pargee/SteamVR_Unity_Toolkit,Innoactive/IA-unity-VR-toolkit-VRTK,Fulby/VRTK