Helper functions to work with HtmlData

• toTextHtml produces a html String
• toTextPlain produces text String with reasonable layout to mimic html (sample)
• toElmHtml produces the regular elm/html Html msg with interactivity intact
• fromHtmlParserNodes takes parsed List Html.Parser.Node and return a List (HtmlData.Html msg)

See them in action at https://html-data.netlify.app converting the same HtmlData.Html msg value into the 3 usages.

BSD

This package needed several dependencies: elm/json, hecrj/html-parser, marcosh/elm-html-to-unicode. I felt it was unnecessary to impose it on the pure data type package choonkeat/html-data; anyone else should be able to write their own functions to produce text/html or text/plain String with different dependencies than what I've chosen.