[Rspamd] Add oletools via olefy, big thanks to @c-rosenberg

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

@@ -0,0 +1,7 @@
+oletools {
+  # default olefy settings
+  servers = "olefy:10055";
+  # needs to be set explicitly for Rspamd < 1.9.5
+  scan_mime_parts = true;
+  # mime-part regex matching in content-type or filename
+}