started converting to use optparse-applicative

This is a work in progress. It compiles and is able to do basic command
dispatch, including git autocorrection, while using optparse-applicative
for the core commandline parsing.

* Many commands are temporarily disabled before conversion.
* Options are not wired in yet.
* cmdnorepo actions don't work yet.

Also, removed the [Command] list, which was only used in one place.

Command/Required.hs

@@ -11,7 +11,7 @@ import Command
 import Logs.PreferredContent
 import qualified Command.Wanted
 
-cmd :: [Command]
+cmd :: Command
 cmd = Command.Wanted.cmd' "required" "get or set required content expression"
 	requiredContentMapRaw
 	requiredContentSet