Haskell praos network simulation (Tuning required)

[Saizan]

First batch of praos visualizations:

• cabal run viz praos-1 for a 2-node simulation relaying a chain across.
• cabal run viz praos-p2p-1 and praos-p2p-2 for WIP simulations of ~100 nodes dinamically generating and diffusing blocks.

CLI:

• cabal run viz now lists the visualization names, as does cabal run viz -- --help.

CI:

• Haskell CI switched to use haskell-actions/setup instead of nix.
• Isolated the formal spec nix setup by using a dummy-project instead of the repo root haskell project. Not a nix expert, others might find a better solution.