Support for Tree Shakable Canvas/WebGL renderer and Font Engines

[wouterlucas]

• Expose Canvas and WebGL Core Renderers under @lightningjs/renderer/webgl and @lightningjs/renderer/canvas respectively
• Allow RendererMain config to accept a renderEngine parameter where the core renderers can be provided
• Expose SDF Text Renderer and CanvasTextRenderer under canvas/webgl exports.
• Allow RendererMain config to accept an array of fontEngines where you can provide 1 or 2 Font Engines.
• Fallback with Canvas still works IF Canvas Text Renderer is provided
• Drop memize dependency to reduce overall bundle size, apply simple caching instead

Todo:

• Check tests, see if text renderer override still works
• Run through some of the resolve code again to make sure we're not introducing new bottlenecks

In my tests the simple benchmark app went down by 20 kb by just using 1 font engine to 40 kb when only using canvas and canvas rendering.

Note: This is a breaking init change, handle with care.