[10.x.x] Universal/shader quality

[Nzollner]

Purpose of this PR

Why is this PR needed, what hard problem is it solving/fixing?
The shader quality solves the problem of creating some predefined tiers for the shader to work with without being platform specific if the user want to change the tier on fx. mobiles.
I'm also adding shadow fading which uses the shader tiers to set which tier should allow shadow fading. The shadow fading is implemented to gradually fade out the shadows such that the user don't see a hard line where there is and isn't any shadow.

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Testing status

I build a game example with an empty shader cache to see if the stripping made the shader cache smaller if shader qualities were left out and also checked if the other qualities than the starting quality worked correctly to make sure there weren't any unintentional stripping that occurred.
I have added the test 131_ShadowFading

Manual Tests: What did you do?

• Opened test project + Run graphic tests locally
• Built a player
• Checked new UI names with UX convention
• Tested UI multi-edition + Undo/Redo + Prefab overrides + Alignment in Preset
• C# and shader warnings (supress shader cache to see them)
• Checked new resources path for the reloader (in developer mode, you have a button at end of resources that check the paths)
• Other:

Automated Tests: What did you setup? (Add a screenshot or the reference image of the test please)

Yamato: (Select your branch):
https://yamato.prd.cds.internal.unity3d.com/jobs/78-ScriptableRenderPipeline

Any test projects to go with this to help reviewers?

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Comments to reviewers

Notes for the reviewers you have assigned.

[phi-lira]

We need to add a doc page to explain the quality settings and what are they enabling/disabling.
We also need to do shader stripping based on quality so we avoid doing 3x shaders in most cases.

[phi-lira]

LGTM. Made minor comments and asked docs/shader stripper.

[martint-unity]

Thanks :) That was fast. :)