MSAA render targets: Resolve the depth texture (if any) and allow for manual resolve

[Popov72]

Note that this is not yet implemented in WebGPU (it's a little more difficult than in WebGL, where ANGLE supports depth texture resolve, which you have to do manually in WebGPU).

[bjsplat]

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[bjsplat]

Snapshot stored with reference name:
refs/pull/15888/merge

Test environment:
https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/15888/merge/index.html

To test a playground add it to the URL, for example:

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/15888/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/15888/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/15888/merge
https://gui.babylonjs.com/?snapshot=refs/pull/15888/merge
https://nme.babylonjs.com/?snapshot=refs/pull/15888/merge

To test the snapshot in the playground with a playground ID add it after the snapshot query string:

https://playground.babylonjs.com/?snapshot=refs/pull/15888/merge#BCU1XR#0

[bjsplat]

WebGL2 visualization test reporter:

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/15888/merge/testResults/webgl2playwright/index.html

[bjsplat]

Visualization tests for WebGPU (Experimental)

https://snapshots-cvgtc2eugrd3cgfd.z01.azurefd.net/refs/pull/15888/merge/testResults/webgpuplaywright/index.html

[sebavan]

Last check would be to be sure Native is still all good

[Popov72]

Last check would be to be sure Native is still all good

cc @bghgary I guess?

[bghgary]

Last check would be to be sure Native is still all good

cc @bghgary I guess?

Native doesn't support MSAA in render targets yet, so there is nothing to test.