LayerManagerService: divided into LayerManagerBase and LayerManagerService

LayerManagerService: divided into LayerManagerBase and LayerManagerService

LayerManagerBase is a static library containing the whole LayerManager
base implementation, e.g. Scene, PluginLoading, ...
This allows other components to directly link to this implementation
(e.g. unit tests)

LayerManagerService contains only the main.cpp file and links to
LayerManagerBase library.

Additionally, some component dependencies have been improved.

Signed-off-by: Timo Lotterbach <timo.lotterbach@bmw-carit.de>