Add JXL support

Converts JXL images so you can view them in the browser.

This is an experimental extension that converts any JXL (JPEG XL) image file in the page to WEBP. It uses the following code for conversion: * https://github.com/niutech/jxl.js You can find my fork here: * https://bit.ly/jxl-as-Chrome-extension Limitations: * Conversion may take a couple of seconds, especially for large images. * No support for animated JXL files. Only the first frame is rendered. * May cause some pages to not load at all. If this happens, please uninstall the extension. This is a work in progress. More explanation on use cases, tips, and workarounds here: * https://r360v.blogspot.com/p/jace.html