Fix stored xss when user import from zone file or dns template editor

See merge request webdev/ispconfig3!2

Filter HTML tags in FAQ questions when admin adds FAQ articles as HTML is required for answers only.

Fixed XSS  vulnerabilities

See merge request ispconfig/ispconfig3!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).