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

Fixed styling errors with too less indention. Maybe copying text between phpStrom and Sublime changed the indention.

Refs #7634. Refactor. REST form/id's are now in STORE_CLIENT. Unit Tests will fail - not updated to new function.

Refs #7634. Session Timeout zu kurz. Add logout of FE user. Logout happens not directly on the first call, but on the second or third page access.

B7634. Fixes #7634. Session Timeout zu kurz. The bug was probably not a bug, but a too short timeout together with an misleading exception (logout and in - but reload the page also leads to valid page). The fix is 'take the system default (php.ini) and set that one'.

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