Iris Website Reform

We had a long discussion on Mattermost today discussing potential improvements to the website. Some of the take-aways include:

• We'd like to move to a static site generator (Jekyll, or something else if someone makes a good pitch).
• We'd like to split the website into sub-pages, as the list of papers is getting too long.
• We'd like to have the website repo public for contributors. I think it would make sense to have it in the Iris organization here on MPI's GitLab.
• In terms of content, the concern that triggered this discussion was along the lines of "(some) people think Iris is just for academic/toy/ML-like languages". We should probably put the fact that Iris is very flexible front and center, maybe by picking a few papers to display on the front page that use Iris for various models of real-world definitely-not-toy languages (RustBelt for Rust, runST for Haskell, DOT for Scala, "Non-Determinism in C Expressions" for C, Goose for Go, and once that paper exists RefinedC for C).
• We could also highlight the different kinds of properties people verify in Iris (type system soundness, refinement, verification of concurrent algorithms, non-interference, ...).

I expect I will take the lead on setting up the infrastructure for wiring up GitLab with Jekyll and GH pages, and @robbertkrebbers offered to take the lead on the content side of things.