Check missing config options in template

[cderv]

Template is currently out of date with the one in Pandoc: https://github.dev/jgm/pandoc/blob/master/data/templates/default.revealjs

Probably because of the reveal.js version.

However, some useful options are missing like the one for navigation: https://revealjs.com/config/
See #110

Configuration options should be checked.