[Web] Add system mails (send mails to all mailboxes via LMTP)
[Web] Allow to add more administrators
[Web] Fix domain administrator editing
[Web] Remove some foreign keys
[Web] Remove username from API
[Web] Remove more .php extension from code
[Web] More minor fixes
- use $autodiscover_config everywhere
- non-443 HTTPS ports in autoconfig etc.
- disabling POP service via SRV record
- fix display name in Outlook IMAP autodiscover
- allow multiple calls to TLSA generator and support Sieve STARTTLS
- iOS mobileconfig generator