Implement ResizableImageExtension to properly integrate with flexmark-java

[vsch]

Current implementation does not follow the proper inline parser extension model

One option is to integrate the =#x# syntax into the core parser, enabled via an option and mark the ResizableImageExtension as deprecated. Otherwise,

• Change: implement ResizableImageExtension to properly integrate with flexmark-java
  extension model.
  • Change: implement proper InlineParser handling of ref based nodes.
  • Change: make ResizableImage be an extension of Image node with all the source
    elements that make up the node for tracing back to source.
  • Change: an image without resize syntax should be parsed as an Image not
    ResizableImage
  • Add: all necessary handlers to allow formatting, and html to md conversion
  • Add: tests to make sure it works in links and as reference, with proper AST generation.