Make a little overlay to show diagnostics

[hukasu]

Objective

LogDiagnosticsPlugin prints the values on the DiagnosticStore to the console, which is spam-y, create an alternative that is visual

Solution

Create RenderAssetsOverlayPlugin to create an UI that presents the data for the MaterialAllocatorDiagnosticPlugin::<StandardMaterial> and MeshAllocatorDiagnosticPlugin on a draggable and collapsable window

Testing

Enabled it on the many_foxes example

Showcase

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[alice-i-cecile]

Part of me thinks that we should use the Name component instead, but I won't block on that.

[alice-i-cecile]

I think this window would look a bit nicer with slightly rounded corners.

[IceSentry]

I would also note that the log diagnostic plugin can measurably impact performance every time it logs things to the console so having something that doesn't need to do IO is much better to report performance metrics.

[alice-i-cecile]

@hukasu feel free to resolve conversations when the feedback has been addressed, so we can quickly tell the status of work items when reviewing :)