feat: enabling group macros on sasjs/server

This PR updates ms_getgroups with a user filter, and ms_getusers with a group filter. ms_adduser2group was also created to faciliate the necessary test(s).

tests/serveronly/ms_runstp.test.sas

@@ -34,7 +34,7 @@ options mprint;
 )
 %mp_assertscope(COMPARE)
 
-libname webeen json (weboot);
+libname webeen json fileref=weboot;
 
 data _null_;
   infile weboot;