Set up GitHub Actions to deploy on gh-pages

[maximelefrancois86]

This script does:

1. download the latest version of jena
2. for every turtle file in the repository, generate RDF/XML, N3, N-TRIPLE, JSON-LD versions
3. push automatically to the gh-pages branch

[maximelefrancois86]

See how it works at

• https://github.com/maximelefrancois86/bot/runs/468045887?check_suite_focus=true
• ---> https://maximelefrancois86.github.io/bot/

[GeorgFerdinandSchneider]

This should be very good. Thanks for preparing

@maximelefrancois86 do we have to revise/ change the code when merging to BOT or is it OK to simply merge this?