Add support for previewing presentations in asciidoctor based on asciidoctor revealjs

[ulfwestermark]

Developers need to do presentations quite often. What would be more natural
than writing them in Asciidoctor in IntelliJ and managing them in Git ?

A similiar solution is available in Visual Studio Code vscode-reveal
that is based on Markdown. However that forces developers to use Visual Studio Code and Markdown ;-)

The underlying component for this should already be in place in terms of Asciidoctor RevealJS and its Javascript implementation.

Suggestion:
Add preview of slides written in Asciidoctor RevealJS