Adding canOpenURL to the Dependency module to complete the logic chain with existing openURL

[ylorn]

Currently the openURL dependency just blindly open the given URL without checking the existence of the target destination. Can we add the canOpenURL to the dependencies as well so that it comes handy when such check is needed? I understand the counterparts might be missing for other platforms like macOS/tvOS/watchOS, but it seems an essential function missing from the openURL. Maybe a OpenURLClient as a single dependency that provides both canOpenURL and openURL?