Investigate upgrading to newer PIXI version

[vulture-boy]

Our current PIXI version is about 3 iterations behind. We would need to perform some refactors, but it may improve our site stability if we are running on later versions of the library and the filter addition we use.

[vulture-boy]

Updating to 5.3.12 is safe.

[vulture-boy]

Seems like if we can update to v6 or later we might be able to get GIF support
https://userland.pixijs.io/gif/docs/

[vulture-boy]

GIF support is setup now so upgrading for it is no longer a motivation.