Refactoring from Ossmeter to Scava breaks the MongoDB dump

[tdegueul]

The MongoDB dump currently used in the Docker images explicitly references Ossmeter's types (typically through the _type field in collections, eg. "_type" : "org.ossmeter.repository.model.github.GitHubRepository").

These should be updated to match Scava's new names, eg. "_type" : "org.eclipse.scava.repository.model.github.GitHubRepository". In the meantime, the dump cannot be used with the new platform as it cannot find the appropriate types to "parse" the data from the DB.