feat: enabling leading blanks in mp_ds2csv. Also tests for mp_ds2csv and mp_testervice.sas, and strict mode fixes elsewhere

base/mp_deletefolder.sas

@@ -51,6 +51,7 @@
     data _null_;
       set work.&tempds end=last;
       length fref $8;
+      fref='';
       rc=filename(fref,filepath);
       rc=fdelete(fref);
       if rc then do;