Improve handling of multiple / no From addresses (#3667)

* Treat multiple From addresses as if there was no From: addr

* changelog

* Don't send invalid emails through the whole receive_imf pipeline

Instead, directly create a trash entry for them.

* Don't create trash entries for randomly generated Message-Id's

* clippy

* fix typo

Co-authored-by: link2xt <link2xt@testrun.org>

CHANGELOG.md

@@ -4,6 +4,10 @@
 
 ### Changes
 
+- If an email has multiple From addresses, handle this as if there was
+  no From address, to prevent from forgery attacks. Also, improve
+  handling of emails with invalid From addresses in general #3667
+
 ### API-Changes
 
 ### Fixes