fix(ui): Image scaling tweaks for sharper pixels

[ashquarky]

Resolves #XXX

Changes:

General improvements to image scaling and handling.

• Introduce "big" images - 2x nearest upscales for Wii U, since that WebKit can't do image-rendering and thus always uses blurry filtering. For most of our images - especially paintings - this is terrible. Instead, 2x them serverside (so paintings become 640px) and tweak the portal layout to display them 1:1 at that size.
  • Also helps a lot with lower-res 3DS screenshots.
  • Increases page weight, but sharp rendering of paintings is kinda essential for the Miiverse aesthetic, so..
• Introduce 48px and 96px icons (used in loads of places in the UI, but can't actually use them yet since none exist on CDN. Migration needed?)
• Bump JPEG quality for screenshots (again)
• Got the aspect ratio of the 3DS top screen wrong in feat(ui): Image processing improvements #161, oops
• Tweak 3DS community layout to display icons at 64px (unscaled)
• Don't send debug.js to Wii Us

We've stacked up a few changes to image rendering, but the frontend still has to support all the legacy options. If these quality settings sit well with the users, we may want to consider doing a bulk migration of the historical post attachments and replacing them on the CDN. Then we can assume all the formats we want are there and don't need to worry about fallbacks.

Filed as a draft against a work branch for early review and to get the right diff, can change base to dev once #332 lands.

• I have read and agreed to the Code of Conduct.
• I have read and complied with the contributing guidelines.
• What I'm implementing was an approved issue.
• I have tested all of my changes.

[suprstarrd]

Don't send debug.js to Wii Us

But I like putting wiiU in my wiiU!