Expose sampler/mipmapping options for entities with material

[OmarShehata]

This came up on the forum. Right now if you're creating an entity with a textured material on it, there's no way to control the sampler that the texture uses, so there's no way to set up mipmapping for it. You can't do this from the primitive API either because Material.js does not expose the sampler as an option.

[mramato]

Step one would definitely be to add it to the Primitive API. The Entity API mostly just sits on top of that. Most things in the Renderer are private for a reason so we do have to be careful and think through what we expose. That being said, TextureMinificationFilter is already public and exposed as part of the ImageryProvider API, so if it's just a matter of allowing that to be set in Materials, it's probably not that big of a change.

[OmarShehata]

Came up again on the forum:

I have relatively low resolved textures that look horrible (not usable) when stretched over a larger rectangle