GS:MTL: Give labels to textures

[TellowKrinkle]

Description of Changes

Adds labels to textures based on their usage and a counter

Rationale behind Changes

If a texture doesn't have a label, Xcode's GPU debugger gives it the amazing label of sprintf(label, "Texture %p", this), which is very non-memorable and makes keeping track of which textures are going where much more painful than it needs to be.

Suggested Testing Steps

• Take a gpu trace and look at it in the Xcode trace debugger

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  After

  

[stenzek]

I've been wanting to do something like this at the GSRenderer/GSTextureCache level for a while, label the textures with the BP, format, etc.

Problem is, they can get reused within the same frame, and the labels are set immediately, so you only have one label per frame..

[stenzek]

I'm going to move this to the base texture class, so that all renderers get the debug names, but easier to merge now rather then rebase later.