[TASK] Raise BE user session timeout to 8 hours

The current limit of an inactive user of 1 hour is not practical for a regular
editor. Instead, a default value of 8 hours fits more to a current work day.

Resolves: #82654
Releases: master
Change-Id: I2b0911f72771ffee7bd76b14de055a8a8e3f280b
Reviewed-on: https://review.typo3.org/54266


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>