[Web] Add multiple DKIM at once (+ button to auto-fill missing keys)

[Web] Duplicate DKIM keys from a single domain to a single or multiple domains
[Web] WIP: Started Ratelimit rework
[Web] Show RL in overview of mailbox and domains
[Web] Move RL function out of mailbox functions file
[Web] Some language fixes/changes

data/web/css/mailcow.css

@@ -101,6 +101,7 @@ legend {
   -ms-user-select: none
   -o-user-select: none;
   user-select: none;
+  font-size: 12pt;
 }
 .navbar .navbar-brand {
   padding-top: 5px;