Add support for webp image format

[styfle]

It would be great for photon to support WebP image format now that most web browsers support it.

[daggy1234]

Hi, currently the image crate that photon uses for encoding and decoding of images doesn't support saving images as webp (no encoding) but can decode them (open webp images).

https://github.com/image-rs/image/#supported-image-formats

[mirzap]

It would seem webp encoding has been implemented in image create https://github.com/image-rs/image/commit/e9ccfcfc30950fa242957d881195bb495abaf649

[dtruffaut]

Very interested in this. Let us know when it works !

[RaphaelBronsveld]

Interested in this as well!

[daggy1234]

Okey! I'll start testing webp and see how it performs.

[aliflux-omo]

Hi, is there any update on webp support?

[ccbikai]

Hope webp can be supported

https://github.com/image-rs/image/blob/master/CHANGES.md Version 0.24.4 New Features:

Encoding for webp is now available with the native library. This needs to be activate explicitly with the web-encoder feature.

[yangm2]

Looks like #164 resolves webp encoding