Implementation of the IStorageProvider interface using Eclipse file resources as storage mechanism for models.

This storage provider searches all projects in the Eclipse workspace for model files. Only files in the project's root folder are considered. For each such files the set of registered eclipseResourceStorageLocationProvider extensions is asked whether the respective file should be considered a model file. This extension mechanism is used to allow different tools to use different file extensions for their models, e.g., tool A uses *.toolA, while tool B uses *.toolB files.