DirectoryPath issues on windows

[pcprinz]

Description of the issue

The example app reveals that on windows the DocumentDirectoryPath doesn't return the path to the documents but <user>/AppData/Local/Packages/<package-id>/LocalState. On the other hand, according to the README the ExternalDirectoryPath should be Android-only but returns the actual directory path.

Possible solution

• The DocumentDirectoryPath should return the actual directory path which is returned by ExternalDirectoryPath
• The <user>/AppData/Local/Packages/<package-id>/LocalState should be returned by another Constant (to be clarified)