chore: URP update - replace obsolete RenderTargetHandle with new RTHandle

[pravusjif]

Note: this branch uses the project with Unity version 2022.3.6f1

• Since URP 13 Unity marks RenderTargetHandle class as obsolete and commands to use RTHandle instead, but several things work differently with that new class. With Unity 2022.3.6, URP 14.0.8 is used.
• I made a 15hs~ effort to try to convert the project RenderTargetHandle usages to the new RTHandle way and managed to avoid any runtime error but the outline screen effect (used for hovered avatars) is still not rendering anything...
• Some basic and straightforward translations from the old system to the new one can be found in this forum post.
• This PR was created from the test/perf-profiling-unity2022.3.4f1 branch so that it only contains the RTHandle file change replacements and is easily checked to continue this work in the future

Main problems found

• If we use cmd.GetTemporaryRT() for some reason the target RTHandle doesn't get any render texture assigned (its .rt property is null), and later when trying to use Blit() with that RTHandle in runtime, we get a Value vannot be null fatal error due to the .rt property being null.
• If we use RenderingUtils.ReAllocateIfNeeded() instead of cmd.GetTemporaryRT() (as Unity does in many replacements on their own PR) we get a render texture assigned to the .rt property (getting rid of the null error) but the Outline Screen Effect Feature still doesn't render the outline when hovering an avatar...

Useful links as guidelines to continue this migration in the future

• https://forum.unity.com/threads/rendertargethandle-is-obsolete-deprecated-in-favor-of-rthandle.1211052/#post-7737570
• https://docs.unity3d.com/Packages/[email protected]/manual/upgrade-guide-2022-1.html
• Unity's own translation from RenderTargetHandle to RTHandle PR: Unity-Technologies/Graphics@d48795e#diff-922e8cb79285d375cad88e469448eebfc9aac59f470810a027d6d70113ed6a4b
• https://docs.unity3d.com/Packages/[email protected]/api/UnityEngine.Rendering.RTHandle.html

[github-actions]

After the CI passes:

Web

This branch can be previewed at:

• https://play.decentraland.org/?explorer-branch=chore/URP-update-replace-RenderTargetHandle-with-RTHandle
• https://play.decentraland.zone/?explorer-branch=chore/URP-update-replace-RenderTargetHandle-with-RTHandle

Desktop:

If you have the launcher installed (download launcher) you can press open on the following link:

• Open custom protocol
• Open custom protocol with Developer Mode

SDK 6/7:

• Open SDK7 scenes playground
• Open SDK7 scenes in preview
• Open SDK6 scenes in preview

More

• Code coverage report: https://renderer-artifacts.decentraland.org/branch-coverage/chore/URP-update-replace-RenderTargetHandle-with-RTHandle
• Benchmark report: https://renderer-artifacts.decentraland.org/branch-benchmark/chore/URP-update-replace-RenderTargetHandle-with-RTHandle/index.html