Implement react-visual

[weotch]

• Basic image rendering
  • What should the image component be named? SomethingImage... maybe AutoSrcSetImage or PictureImage
• Wrap image in picture by default and add srcset to a source rather than on the img
  • Implement srcset
  • Match the default srcset widths of nextjs ... I don't think I need to make this an explicit prop even though it could be nice in tests
• Add mimeTypes prop that will get passed to imgLoader for rendering source tags targeting different mime types (like by Contentful)
• Add responsive image props that generate additional sources as well
• Support image fit and position
• Support priority
  • See next/image
  • This needs a framework to do anything significant, so I think all this does is toggle the native loading prop like next/image does here
• Support placeholderData
  • Not that I can generate from Contentful at the moment. Maybe I use https://plaiceholder.co/docs?
  • Maybe this shouldn't be the concern of this component? Or it has as different prop for rendering just a flat color value?
• Support imageLoader prop which generates the srcset when provided.
  • Use next/image default sizes
  • This loops through the various mimeTypes and responsive asset types to generate all combinations of each with the same srcset values but different CDN rules for the mime format and source asset
• Update docs that mention no react-visual component
• DRY up the custom Cypress commands #27
  • DRY up testing of stuff that is the concern of the VisualWrapper, like all the expanding / fixed size stuff, into it's own test file