[Dovecot] use python bootstrapper to start DOVECOT container

data/conf/dovecot/config_templates/global_sieve_after.sieve.j2

@@ -0,0 +1,30 @@
+# global_sieve_after script
+# global_sieve_before -> user sieve_before (mailcow UI) -> user sieve_after (mailcow UI) -> global_sieve_after
+
+require "fileinto";
+require "mailbox";
+require "variables";
+require "subaddress";
+require "envelope";
+require "duplicate";
+
+if header :contains "X-Spam-Flag" "YES" {
+  fileinto "Junk";
+}
+
+if allof (
+  envelope :detail :matches "to" "*",
+  header :contains "X-Moo-Tag" "YES"
+  ) {
+  set :lower :upperfirst "tag" "${1}";
+  if mailboxexists "INBOX/${1}" {
+    fileinto "INBOX/${1}";
+  } else {
+    fileinto :create "INBOX/${tag}";
+  }
+}
+
+if duplicate {
+  discard;
+  stop;
+}