- added limit for letsencrypt and directive snippets selector to client limits
- hide ssl tab if letsencrypt is selected

missing menu for ftp stats

Hi, 

I forgot to send /interface/web/sites/lib/module.conf.php.
Now the ftp stat can be accessible by interface


See merge request !280

fix some bugs in commit f1926a01 - #3716



See merge request !278

postfix: add smtpd_helo_restrictions, enable smtpd_reject_unlisted_sender

add smtpd_helo_restrictions to postfix config, including helo_access and blacklist_helo config files

enable smtpd_reject_unlisted_sender and stricter defaults on a few other settings

See merge request !275

Allow HTML based welcome messages

I needed a HTML based welcome message, so I added this to mail_plugin.inc.php 

I hope this is the correct approach.

In addition to /conf-custom/mail/welcome_email_DOMAINNAME.txt and /conf-custom/mail/welcome_email_LANGUAGE.txt one may place a /conf-custom/mail/welcome_email_DOMAINNAME.html or /conf-custom/mail/welcome_email_LANGUAGE.html file to allow HTML based welcome messages.

See merge request !276

In addition to /conf-custom/mail/welcome_email_DOMAINNAME.txt and /conf-custom/mail/welcome_email_LANGUAGE.txt one may place a /conf-custom/mail/welcome_email_DOMAINNAME.html or /conf-custom/mail/welcome_email_LANGUAGE.html file to allow HTML based welcome messages.