Different approach to commands (#34)

* different approach to command types (WIP)

* PartyProtocol class and other commands

* pretty-print scenarion

* remove old files

* remove unused prf/predicate templates

* remove NoImplicitePrelude from doctest (although there are no doctests atm)

definitions/app/api-docs/Main.hs

@@ -0,0 +1,16 @@
+module Main where
+
+import Simplex.Messaging.ServerAPI
+
+import Servant
+import Servant.Docs
+
+apiDocs :: API
+apiDocs = docsWith
+            defaultDocOptions
+            [serverApiIntro]
+            serverApiExtra
+            (Proxy :: Proxy ServerAPI)
+
+main :: IO ()
+main = writeFile "../simplex-messaging-api.md" $ markdown apiDocs