dosutils: add creator and supporting NCP helpers

Add the CREATOR utility and wire it into the DOS tools build and NET
command dispatch.

Extend the client-side NCP helpers with the calls needed by the new and
updated tools, including DOS namespace information and effective-rights
queries. Also update MAP handling for automatic drive mappings used by
the login script.

This commit contains the tool/source support only. The DOS baseline test
suite is kept separate and will be added in a follow-up commit.

net.c

@@ -41,6 +41,7 @@ static struct s_net_functions {
 {"REMOVE", "remove trustee",                        func_remove , 0},
 {"NDIR",   "list directory contents",               func_ndir   , 0},
 {"RIGHTS", "display effective file/directory rights",func_rights, 0},
+{"CREATOR","display or set creator/modifier/archive ids",func_creator,0},
 {"SLIST",  "list servers",          		    func_slist  , 0},
 {"PASSWD", "change password",          		    func_passwd , 0},
 #if 1