Refactor Painter away

[jfirebaugh]

This refactor capitalizes on the asynchronous rendering work, particularly #9327, to simplify the set of rendering-related classes. In particular, it moves all of the code in Painter to better places:

• Painter::render<LayerType> becomes Render<LayerType>Layer::render. As a special case, there was some fill-extrusion-related code that wasn't in Painter::renderFillExtrusion -- that moved to RenderFillExtrusionLayer::render too.
• Painter::renderTileDebug had two overloads. The one for rendering tile debugging becomes RenderTile::finishRender. The one for rendering image source debug borders becomes RenderImageSource::finishRender.
• Painter::render{ClippingMask,Item,Pass,ClipMasks,DepthBuffer} were inlined into Painter::render.

Finally, what was left of Painter itself was parceled out:

• The one-off OpenGL objects moved to RenderStaticData
• The per-frame data that all the various render methods need moved to PaintParameters (which we should next rename to RenderParameters)
• That leaves the main Painter::render method, which was merged into Renderer::Impl

[ivovandongen]

Cleans up nicely!

[ivovandongen]

nit; rename parameter