ExplorerCreateFile: Save XML files from clipboard

[ewerybody]

We already can save xml <img data in base64 png and jpeg format.
As it also starts with < that might indicate other xml code right away which you can in fact not paste as text to a file name anyway!
So lets branch off this kind of stuff into a new function inside of ExplorerCreateFiles clipboard handling dealing with all of these <..> things.

I'd guess these then would be:

• xml code
  • img base64 encoded with these formats
    • png
    • jpg
  • html
  • svg
  • xml
• binary image data

Then lets pop a menu if it cannot be determined correctly to let the user decide what kind of file so save to.
Or lets just do this with the text dialog like in the image bytes.

Amend the documentation page accordingly.