[TASK] Update layout of navigation in DocHeader

Use Bootstrap grid for arrangement of navigation items.
Shorten the characters of the current page title in DocHeader to
title length defined in user settings or default to '50'.

Resolves: #79849
Releases: master
Change-Id: I0825818cd961b8bb7f928cb1389537506d5ed40b
Reviewed-on: https://review.typo3.org/51831


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Joerg Kummer <service@enobe.de>
Tested-by: Joerg Kummer <service@enobe.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>