[BUGFIX] FAL Upgrade Wizards do not set pid

The sys_file_reference records are originally set to
be placed on rootLevel, the upgrade wizard does
exactly that.

However, the concept in this case is flawed
- When creating new sys_file_reference records via IRRE,
   the sys_file_reference is stored on the page
- When copying moving e.g. a tt_content record, all its
   child elements are placed on that new page as
   well (so this works)
- rootLevel restriction is not needed in this case

The patch does the following:
- Modify the existing upgrade wizard to place the
   sys_file_references on the pages of the foreign
   tables (tt_content pid)
- the rootLevel flag for sys_file_reference is removed
- Add a new upgrade wizard is added to ensure the
integrity of the sys-file-reference pids

Releases: 6.1, 6.0
Resolves: #46497
Change-Id: I2ee435907c6381becd29664e901b1bd8fd62174a
Reviewed-on: https://review.typo3.org/19130
Reviewed-by: Henrik Ziegenhain
Reviewed-by: Simon Schick
Reviewed-by: Michael Staatz
Tested-by: Michael Staatz
Tested-by: Henrik Ziegenhain
Reviewed-by: Benjamin Mack
Tested-by: Benjamin Mack
[TASK] Remove unneeded backupGlobals from Unit Tests

Change-Id: Ib15d118cd28a455fb5125fc51580382ad72d1d26
Resolves: #46593
Releases: 6.1
Reviewed-on: https://review.typo3.org/19215
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn