de/de-informal: Re-apply the updates of ba09710ad34bb383ae3526e84490a3d545f78866

Revert "German language update"

This reverts commit ba09710ad34bb383ae3526e84490a3d545f78866.

Conflicts:
lib/plugins/authad/lang/de/settings.php

Finnish language update

German language update

Dutch language update

Latvian language update

Korean language update

de/de-informal: config plugin - Clean up the TOC in the configuration page / No need to add "Konfiguration" or "Plugin" to every element if the heading tells you that.

German (informal) language update

Korean language update

Brazilian Portuguese language update

French language update

Traditional chinese language update

Italian language update

fix security caution for 'remote' setting (was 'xmlrpc')

Italian language update

replace preset _cautionList property with _caution config metadata parameter, plugins can now easily set cautions on their settings

fix security caution for 'remote' setting (was 'xmlrpc')

FS#2722 add settings_regex class, use it for hidepages

remove no longer used email pattern, validation is done by mail_* functions

remove php_strip_whitespace() alternate, no longer required as php min req't ensures its always present

add comments for recent settings class additions to extra.class.php

removed a bunch of functions which were deprecated in 2005/2006

improve comments on settings::update() method

tidy up authtype setting class (incl. fix issue with auth change/logoff occurring when only one auth plugin is enabled and other settings are updated)