[TASK] Renamed the domain model

Changed the domain CssFile model to Asset

Change-Id: I24dc6ef1b79a7eb541cf10d7e51c8508875f29a3
[TASK] Adapted to Neos update

Sprint: 2013-30
Revert "[TASK] Adapted to Neos update"

This reverts commit 9256415308a27bec75f29c8969986fb27495b189
[TASK] Adapted to Neos update

This reverts commit 7055eb426710cddee37f4f61c267692fc6527e40.