OCaml: Handle some edge cases; refactor parser, main.ml; add config fetcher

ocaml/lib/system/process/command.ml

@@ -17,22 +17,3 @@ let format (command : command) : string =
 
 let format_many (commands : command list) : string list =
     List.map format commands
-
-let check_su_command (schema: schema): schema =
-    let command = schema.input.configuration.main.su_command in
-    let path = Reader.read [||] ("which " ^ command) in
-    try Unix.access path.output [Unix.X_OK]; schema
-    with Unix.Unix_error _ -> elog "";
-        {
-            schema with
-            output =
-                {
-                    schema.output with
-                    main =
-                        "Super user command " ^ command ^
-                        " not executable at path '" ^ path.output ^
-                        "' (exit status " ^ path.status ^ ", stderr: '" ^
-                        path.error ^ "')\n"
-                };
-            meta = { schema.meta with status = 1 };
-        }