Feat/avif convertion

[JohanHjelsethStorstad]

This PR converts all images to avif on upload. We know have three image sizes + original. This PR also fixes:

• horrible admin-layout on images/collections/id page.
• Refactor of image display
• Fixes #103.
• User can now see all image sizes when viewing an image on the images page.
• The editing of cmsImage is smoother

[JohanHjelsethStorstad]

I'll open for more formats