munin: refactor package and add nixos service
Merge pull request #1090 from NixOS/munin-rework

munin: refactor package and add nixos service
haskell-data-pprint: update to version 0.2.3
haskell-pandoc-citeproc: update to version 0.1.2.1
haskell-pandoc-types: update to version 1.12.3
haskell-path-pieces: update to version 0.1.3
haskell-uuid: update to version 1.3.0