rspamd: More comprehensive attachment handling (#3273)

- block all Office documents with macros
- don’t just block all doc files
- mark some more Windows executable extensions as bad

data/conf/rspamd/local.d/external_services.conf

@@ -4,4 +4,6 @@ oletools {
   # needs to be set explicitly for Rspamd < 1.9.5
   scan_mime_parts = true;
   # mime-part regex matching in content-type or filename
+  # block all macros
+  extended = true;
 }