Native WebP support

[rhoerr]

Description

Support uploading, handling, browsing for WebP images

And maybe AVIF while we're at it.

Expected behavior

Ability to use WebP images on products, content pages, etc.

Benefits

No response

Additional information

No response

Release note

No response

[jeanmarcos-dev]

Opened a PR for this: #317.

WebP and AVIF are accepted everywhere Magento takes an image, and — off by default — Magento
can also write a WebP/AVIF copy of each cached catalog image for the web server to serve by
Accept negotiation. Instead of hardcoding webp in the ~20 places the extension list was
duplicated, it adds a format registry; AVIF then cost one virtual type plus one GD callback.

Worth knowing up front: AVIF is not always smaller (WebP wins below ~200px) and encodes
noticeably slower, which is why the copies are opt-in.