Add the template for the "LIPIcs–Leibniz International Proceedings in Informatics"

• Template: https://www.dagstuhl.de/en/publications/lipics and https://submission.dagstuhl.de/documentation/authors
• Author guidelines: http://drops.dagstuhl.de/styles/lipics-v2019/lipics-v2019-authors/lipics-v2019-authors-guidelines.pdf

I'm keen on working on this myself, but don't know when in the next months I'll get around to do it, so wanted to leave this here to potentially coordinate with others who'd work on this.

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