Implements #9679: formModeGlobal is now also used via STORE_USER - set formModeGlobal systemwide for a specific user (session).

Fix unit tests: replace uniqid() by uniqIdQfq() which delivers a constant id in case of running unit tests

Fixes #7925. a) change CWD during split reduced to splitting only. b) fixed problem in mkDirParent() with absolute paths, c) make logger independent of CWD, d) fixed problem with `mktemp --tmpdir`(difference Ubuntu 16 / 18) by using PHP function, e) fixed some 'undefined index' problems

Refactor to use form.restMethod instead of form.permNew|edit=rest. Next step will be to eliminate formMode=FORM_REST

Fixes #7864. 'required'-FE Elements, deactivated via formModeGlobal=requiredOff, now gets class 'required-field'. The final 'required' mode is still temporarily disabled.

Refs #7743. Detection of 'pattern error' on per QFQ default, custom instance wide, per form or per FormElement - per FormElement overwrites other. System specific generated overwrites QFQ static default, instance wide default. Move default pattern to constants.

Refs #7743. Add unit tests. Make default error text more specific (only if default error text is not explicit set in config, form or form-element)

Refactor: Manual.rst update config variables (reorder), add 'qfqLog'. Support.php: formSubmitLog hardcoded to fileadmin/protected/log. DOCUMENTATION_QFQ > SYSTEM_DOCUMENTATION_QFQ. Remove config var 'logDir'.

F4906 Php Session Timeout: can be specified globally in configuration and per form. Affects only logged in FE User.

Logger.php: remove UserAgent - that one is logged in FormSubmitLog Table. Add 'cookie' to filter individual actions.

F4901: implement split with 'convert' (jpeg). Refactor chmod(), unlink(), rename(), rmdir(), copy() to use by QFQ version which throws an exception.

B6929 - Treat single file argument like several file argument (savePdf: copy, not move) - refs #6929, closes #6929

Upload: rename 'chmod' to 'chmodFile'. Implement 'chmodDir'. Permissions applied for all new created directories.