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

- 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)

- added module_name parameter on registerEvent

- made placeholders visible for apache, too
- added event raise at formdef loading (on_before_formdef and on_after_formdef)
- added possibility to put plugin files into module/lib/plugin.d/ directory