[BUGFIX] Remove wrong replace for lw/typo3cms-installers

The composer.json stated that this package could replace
lw/typo3cms-installers. This is however (currently) false, as e.g. a
downloader for t3x files is missing, making it impossible to install
extensions from TER. Therefore, the replace-dependency is removed until
this package can fully replace Lightwerk's installers.