Jitter shadow map dithering pattern across frames when TAA is enabled

[clayjohn]

Supersedes: #61834
This closes godotengine/godot-proposals#4179 and closes #53534.

Credit to @Calinou who did most of the work. I just did some final cleanup to improve the quality before it was ready to merge

I ended up rebasing while working on the improvements described in #61834 (comment) so I figured it was less work overall for us to open a new PR.

This PR builds on the current state of #61834, see that PR for a full description/history

[hsvfan-jan]

Will the improved documentation of this comment of yours in #61834

We need to document that FSR2.2 at 1.0 scale is more sensitive to high contrast areas than TAA or FSR2.2 at lower scales as this will impact many users.

be included in another PR? I think it wouldn't be obvious why these artifacts will be found in various strengths in different locations in a level so documenting it would be great.

[akien-mga]

This is co-authored by Clay and Hugo so it's pretty much peer reviewed already. Seems simple enough for me to approve for merge.

[clayjohn]

Will the improved documentation of this comment of yours in #61834

We need to document that FSR2.2 at 1.0 scale is more sensitive to high contrast areas than TAA or FSR2.2 at lower scales as this will impact many users.

be included in another PR? I think it wouldn't be obvious why these artifacts will be found in various strengths in different locations in a level so documenting it would be great.

Yes, the docs are hosted in a separate repository. So the documentation update will necessarily be in another PR

[akien-mga]

Thanks!