[TASK] Rename classes with the same name

We have 3 implementations of the \localPageTree
class in the global namespace:
- db_new.php
- move_el.php
- class.browse_links.php

This patch renames classes from db_new and move_el files.
It should not break non core scripts, as both db_new.php
and move_el.php are entry points, so classes defined
there should only be used in the entry point scope.

The class 'localPageTree' from the class.browse_links.php
will keep its name, so it can be added to autoload now.

Resolves: #55876
Releases: 6.2
Change-Id: I2e084349b93af212aec85b368e7e3468a76c7a82
Reviewed-on: https://review.typo3.org/27572
Reviewed-by: Markus Klein
Reviewed-by: Alexander Opitz
Tested-by: Alexander Opitz
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind