This PR adds a new pixel art setting and special sampler for sub-pixel pixel art rendering.

Additionally this PR adds MSAA to the framebuffer implementation, giving a nicer look to some graphics when drawing to the quad boundary.

Also fixes an issue with `snapToPixel` where camera did not correctly snap to pixel

Example using the old `antialiasing: false` on pixel art

https://github.com/excaliburjs/Excalibur/assets/612071/c55a09b0-cf7e-409c-a82c-447e0bec198a

New `pixelArt: true`

https://github.com/excaliburjs/Excalibur/assets/612071/eff9f9f3-a731-482a-8e15-e778e60c225e