Fixed XSS  vulnerabilities

See merge request !699

- fixed escaping in lists

- no entities on wordbook entries

- Fixed #4893 Stored XSS issue in email name field

Make log message less confusing when level is only Warning.

See merge request ispconfig/ispconfig3!696

Fix issue when DNS zone import fails silently with OK message if $TTL is missing…

See merge request ispconfig/ispconfig3!695

Fix issue when DNS zone import fails silently with OK message if $TTL is missing from the input file because TTL can not be null when saving SOA to database.
Solution: if TTL is null then simply set it to 1 day - 86400 seconds (as per RFC 1912 recommendations).
I encountered few services that export a dns zone without global ttl set (ex: GoDaddy).

Add NE-Flag to rewrite_to_https

See merge request ispconfig/ispconfig3!693

Restore fpm_group owner-ship

See merge request ispconfig/ispconfig3!675

Option to limit access for remote-user to specified IP(s) / hostname(s) (#4881)

See merge request ispconfig/ispconfig3!683

Exclude le domains

See merge request ispconfig/ispconfig3!682

Stable 3.1

See merge request ispconfig/ispconfig3!681

Conflicts:
	install/sql/incremental/upd_dev_collection.sql

Fixed authenticated user privilegue escalation vulnerability in cron module, fixes #4869

See merge request ispconfig/ispconfig3!680