[BUGFIX] Show guidelines in Adminpanel rendering tree view

The tree guidelines are now properly shown in the TS Tree view
in AdminPanel.
Also not used FontAwesome is removed from AdminPanel


Resolves: #90448
Releases: 9.5, master
Change-Id: I065a65a9b7de049d2c5e325f0ae15d28a2853303
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63355


Tested-by: Christian Eßl <indy.essl@gmail.com>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Christian Eßl <indy.essl@gmail.com>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>