plumb creds from webapp to initremote

Avoids abusing setting environment variables, which was always a hack
and won't work on windows.

Types/Creds.hs

@@ -0,0 +1,12 @@
+{- credentials
+ -
+ - Copyright 2014 Joey Hess <joey@kitenet.net>
+ -
+ - Licensed under the GNU GPL version 3 or higher.
+ -}
+
+module Types.Creds where
+
+type Creds = String -- can be any data that contains credentials
+
+type CredPair = (String, String) -- login, password