Sun Shafts SRP

Sun Shafts SRP is the standard sun shafts Unity effect, adapted for use with Post Processing Stack v2.0 and URP pipeline. The effect will work on all SRPs that are compatible with Post Processing Stack v2.0 and supports both desktop and mobile platforms. Has been tested on Android. Starting with Unity 2020.1, in URP only the integrated post-processing solution is supported and Post Processing Stack is unavailable, so the main effect will not run. Because of this an extra URP native version of the Sun Shafts effect has also been added and is to be used for both Desktop and Mobile.