Bug #5924: change include_once() against include() - second call to include_once just returned 'true'.

Bug #5924 / config.qfq.ini/LocalConfiguration.php: der FormEditor nur mit 'dbIndexData = 1' in config.qfq.ini - several places in formEditor.sql still contained the 'dbIndex...' instead of 'index...'. fixed.

B6168 Configuration language setting ignored: Form and FormElement editor still used uppercase config values for language configuration. Updated to the new camel case notation.

Bug #5890 config.qfq.ini: migrate LDAP credentials too. Extend T3 internal qfq config with 30 'custom'-vars. This replaces the old custom vars in config.qfq.ini

Bug #5890 config.qfq.ini is public readable. Renamed file to config.qfq.php. Implement a basic migration assistant to copy DB credentials to new config.qfq.php. All other values have to be copied to extmanager/qfq-configuration manually.

B5077 Dynamic Update & FE.type=required: Server fixed - a) dynamic calculated modeSql respected, b) formModeGlobal=requiredOff respected, c) dynamic FE with mode='hidden' are not saved anymore.