Feature #4432 - Form Submit Log, as a new FormSubmitLog QFQ-Form, with code in the manual for a FE page to browse the table.
Also added code in the manual for a MailLog FE page.

F6289: show debug button for 'All' and 'Per session'. Remove expired logfiles. Set new form variables FORM_LOG_FILE_ALL, FORM_LOG_FILE_SESSION.

F6289: First runnable version to show the formLog. Log is still empty (nothing submitted). 'per session' / 'all' not implemented.

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

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.

F6100 Url Forward Auto: Update Manual.rst. The F.parameter.saveAndClose has been removed again. Mode 'close' can be assigned statically or dynamic.

Manual.rst: usage of drag and drop.

DragAndDrop.php, QuickFormQuery.php: bug fixes
FillStoreForm.php: no FE on a Form now ok - necessary for dnd sort forms.

DRAGANDDROP.md, PROTOCOL.md: Doc for "drag'n' drop" implementation.
dragAndDrop.php: API endpoint
DragAndDrop.php: Class for implementing drag'n' drop functionality.
Link.php: implement new renderMode=8 - returning only the sip.
QuickFormQuery.php: New entry point for processing "drag'n' drop".

HelperFormElement.php, SessionCookie.php, Html2Pdf.php, Store.php, Constants.php: migrate to camel case on configuration variables.
Config.php: readConfig() reads now config.qfq.ini and T3 LocalConfiguration.php.