[Web] Add more sieve presets

data/web/inc/presets/sieve/sieve_7.yml

@@ -0,0 +1,7 @@
+headline: lang.sieve_preset_7
+content: |
+  redirect "other-address@domain.tld";
+  # Either keep after redirecting:
+  # keep;
+  # Or redirect and drop:
+  discard; stop;