Removes #last_version calls from views
Uses factories instead of creating objects inline in the tests
Removes dependency injection from PackageFactory
Removes dependency injection form StorePackageInformation
Removes dependency injection from the other services
Removes all remaining dependency injection code
Throws specific InvalidPackageException

This allows to catch only this exception instead of all other exceptions
when processing the whole package index
Removes PACKAGE_INDEX constant
Introduces GetCranUrl to generate index and package URLs