[TASK] Switch to json_encode/decode for state saving

Various places (Trees, Inline Data) can be optimized by
using a more "space-saving" and faster approach.

By using json_encode/decode instead of serializing the
data, the stored information in "uc" of Backend Users
will be vastly smaller when dealing with larger installations.

Resolves: #88680
Releases: master
Change-Id: I59e83c8c7615e9da63b04ebb4930c2b68b38ad7c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61220


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Oliver Hader <oliver.hader@typo3.org>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Oliver Hader <oliver.hader@typo3.org>