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

Refs #8348 - Add header, separator and disabled menu entries. Download PDF is ok. New: '||' are required to separate menu entries.

Fixes #8278: Bug 1 - check GET Vars but try to report problem from POST var. Bug 2: writing log message crashed due to not initialized QFQ-config.

Refs #8012: remove unit test for sanitize class 'password' - there is no T3 installation on alfred16. The test can't succeed.

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

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 #6914. Final implemention of customized typeMessageViolation. Incl. unit tests. New escape mode 'C' - escapes ':' by '\'.' - useful for variables in variable definition.

Refs #7743. Move error mesages to Constants.php. Unit tests use those constants now. 'data-pattern-error' only delivered if a 'pattern' is given. 'required' attribute only delivered is set.