Don't crash when attribute count is exceeded

[kkaefer]

With data driven styling, we are dynamically computing shaders with a varying number of vertex attributes. One caveat of that is that the minimum mandated number for vertex attributes in the OpenGL ES 2.0 spec is only 8, as we discovered. Most modern GPUs have a higher limit than that, but there are some older mobile GPUs that only supply the bare minimum (see #9331). @jfirebaugh reworked this in #9433 to limit the number of vertex attributes we're using.

We're throwing with a "too many vertex attributes" error in this case. This PR changes that so instead, we're printing a warning message when the user creates a style that has more attributes than the minimum limit, but we'll still bind them if the hardware supports it. If it doesn't, we won't bind the attributes beyond the hardware limit and instead accept the rendering errors. While this is unfortunate, it's still better than crashing.

[jfirebaugh]

Can we make the warning logic a bit more specific?

• Logging the ID of the layer that has too many data-driven properties would be a big improvement.
• Customize the message based on maxAttributes:
  1. Get GL_MAX_VERTEX_ATTRIBS value first.
  2. If location > maxAttributes, warn with:

  The layer <ID> uses more data-driven properties than the current device supports, and will have rendering errors. To ensure compatibility with this device, use fewer data driven properties in this layer.

  3. Else if location > MAX_ATTRIBUTES, warn with:

  The layer <ID> uses more data-driven properties than some devices may support. Though it will render correctly on this device, it may have rendering errors on other devices. To ensure compatibility with all devices, use fewer data-driven properties in this layer.

[kkaefer]

I made changes to accommodate your request. Since it'd be tricky to loop through the layer name and ensure that the warning would only be printed once per layer during the actual attribute binding, I chose a strategy that uses Attributes::Bindings to determine how many active attribute bindings we have when rendering a layer. This necessitated factoring out the AttributeValues so that they can be accessed while rendering a layer.

[lbud]

FYI @kkaefer I fixed a few compile errors and merged here per @lilykaiser's request 🙇‍♀️

[lilykaiser]

Thanks @lbud !