Add multiview limits and tests

[inner-daemons]

Connections
Closes #7196
Closes #8138

Description
Adds new limits and testing for multiview, add support for more backends (also in naga), add new multiview bitmask renderpass descriptor field for selecting which layers to render to in a single pass.

Testing
There are tests

Squash or Rebase?
Squash

Checklist

• Run cargo fmt.
• Run taplo format.
• Run cargo clippy --tests. If applicable, add:
  • --target wasm32-unknown-unknown
• Run cargo xtask test to run tests.
• If this contains user-facing changes, add a CHANGELOG.md entry.

[inner-daemons]

@cwfitzgerald I left a comment about this in matrix but it got hidden by newer messages. Is it a bad idea to add another multi view related field to a render pass descriptor? This might be a topic worth bringing up in a meeting, I'm not sure. I'm just hesitant to assume that's fine because if I'm wrong then I will have refactored every use of render passes in this entire repo :)

Not urgent of course

EDIT: This has been answered

[inner-daemons]

My web UI doesn't have an "add suggestion to batch" right now for whatever reason. I'm gonna commit everything individually lol since I couldn't figure this out.

[inner-daemons]

@Wumpf Thanks for the review! This this incredibly comprehensive and useful. I'll probably just rewrite major parts of the test/example, since that seems to be the weakest part.

[Wumpf]

thanks for following up on everything! example & test looks a lot nicer now :)
However, I believe you made a mistake and accidentally made the non-continguous mask-test continguous

But I think after that we're done! :)

[inner-daemons]

@Wumpf Great, thanks! Should be good to go soon then

[inner-daemons]

Feature detection is currently broken, gonna look that over and unbreak this bad diff resolution. Then it should be pretty good