Debug browser: Add syntax highlighter

[jakubklimek]

We need to add a syntax highlighter for the debug data, at least for JSON and RDF Turtle (based on file extensions). Here are some options:

• https://highlightjs.org/
• https://prismjs.com/
• Top 5 including the two above https://ourcodeworld.com/articles/read/140/top-5-best-code-syntax-highlighter-javascript-plugins

If Turtle is missing, we can add it to the chosen one

[skodapetr]

@jakubklimek Well, it is just that most of them are focused on highlighting code not file content. So can you add some details on which relevant formats that we want to support those tools support?

[jakubklimek]

The listed ones all support JSON. In addition to JSON, we need the RDF serializations, XML and HTML would be nice (highlight.js supports these). So I see no problem there.

Of course, if we find something usable for us which already supports RDF, the better, but I think it can be added to those listed above, if needed. For instance, I already written a highlighter for Rouge, which is a Ruby-based highlighter used in github pages.

[skodapetr]

Ok, could you please provide a plugin for PrismJs or https://highlightjs.org/ we should be able to get both running - but we may need to test both for performance.

[jakubklimek]

I added Turtle/TriG to Prism (https://github.com/jakubklimek/prism).