Fixed: Issue #3819 v3.1 Unescaped strings in language files after installation vs source throws 500 error

if the filter rule uses "begins with", the regex should be "^$searchterm" instead of " $searchterm"

- ignore limit_client from templates if they don't match client type (client/reseller) (Fixes #3734)

This reverts commit 9d3f2bbc.

This reverts commit aab7e05b.

Posibility to change main-domain of aps-instance over remote (in interface maindomain is always the websites domain but over remote it's now possible to set an alias oder subdomain, that will be used in instance-settings. Important if e.g. wordpress-installation should run unter an aliasdomain instead of the websites domain)