Add html format support for CKeditor

[pdelboca]

Storing the output of the CKEditor in Markdown format was causing lot of troubles. The major one is that ckeditor and other WYSIWYG editors, when creating an output in markdown format they also write some html tags for the style. Example, for images:

<figure class="image image-style-side">![](https://ckan:5000/uploads/showcase_image/2020-05-20-130051.617895Quebrada-Condorito.png)</figure>

This causes a particular problem which is: rendering to html markdown text inside already existing html tags. CKAN renders all the MD correctly but the link inside the figure html element is not rendered into an actual image tag. We can remove the already existing html tags in ckeditor’s output but that forces us to loose the style we give to it in the editor.

This problem of rendering markdown inside html tags is well documented and I have tried several approaches and none was successful so we opted to store data in plain HTML if ckeditor is loaded.

This PR:

• Removes the option to write to MD from CKEditor
• Stores the notes field in plain html to render it in the read view of the showcase
• Adds a new div to render if ckeditor is enabled to use custom ckeditor css described here. (CKEditor uses some special classes that we need to integrate in our UI to actually get what we see)
• Edit the webpack.config.js to create the minified css while running npx webpack --config webpack.config.js
• Adds a new command markdown_to_html to migrate notes from existing showcases to an HTML format

Some images

Todo:

• Add cli tool to migrate previous showcases with markdown notes to html notes
• Add some tests
• Update README

[amercader]

Looks good @pdelboca , just some minor comments

[pdelboca]

Thanks @amercader ! I did those changes so let me know if anything else is needed! :)