[TASK] Remove unused typo3/alt_* files

Remove files that are scheduled for deletion in 4.7 and not
referenced in the core at any place.

Change-Id: I0b6b70aaaf063111ab4e063d39ca116d1e8a0e3d
Resolves: #31298
Depends: #31296
Releases: 4.7
Reviewed-on: http://review.typo3.org/6339
Reviewed-by: Markus Klein
Tested-by: Markus Klein
Reviewed-by: Oliver Klee
Reviewed-by: Helmut Hummel
Tested-by: Helmut Hummel
Reviewed-by: Christian Kuhn
Tested-by: Christian Kuhn