The dkim_select can start with a number, but has to contain atleast
1 letter and has to be between 1 and 63 characters long.

before the regex matched empty entries and entries starting with a number.

Some were already in English, most were still in German.

- removed separate rspamd greylisting setting for policy and respect mail user/alias/forward/catchall setting for greylisting, fixes #5379

- change the way greylisting setting is evaluated (prio is now 1. mail user, 2. mail forward/alias, 3. catchall), fixes #5378