[TASK] Remove tslib directory

The frontend parts are split into EXT:cms and EXT:frontend,
and the legacy directory "tslib" and the constant PATH_tslib
are hardly used anymore.

The patch moves the respective eIDs in the correct folders,
moves index_ts.php into a class and moves the frontend
page template into EXT:frontend. Thus, the tslib directory
can be removed completely.

Additionally an old reference to tslib in indexed_search
can be safely removed as well.

Releases: 6.3
Resolves: #61459
Change-Id: I9c19dcbeb7c18ef24b2fee3f997a12b7b8d0f957
Reviewed-on: http://review.typo3.org/32660
Reviewed-by: Nicole Cordes <typo3@cordes.co>
Tested-by: Nicole Cordes <typo3@cordes.co>
Reviewed-by: Helmut Hummel <helmut.hummel@typo3.org>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>