Change Uid to stateIdentifier because one Uid can occur in the pagetree
many times, for example in DB mounts.
We need to know what node is visible or what node was clicked or what
node was mouse over / mouse leave, e.t.c.

This change also fixes:
- fix MP title position and visibility
- fix changing node name when the same node is multiple in page tree
(pagetree, mount points)
- modified the acceptance tests

Releases: master
Resolves: #83280
Change-Id: I57716db1f2850f0c4b1432651ed391ece5921fec
Reviewed-on: https://review.typo3.org/55020


Tested-by: TYPO3com <no-reply@typo3.com>
Tested-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>