This gives new support for the new XDG_STATE_HOME addition to XDG_BASE_DIRS
which allows applications to use this without breaking because they would
assume $HOME/.local/state which may be unavailable to the flatpak
This adds it as .local/state as to make --persist=.local/state the same behaviour
as in new flatpak. This in turn means that the transition should be seamless between
old and new flatpak.
This also has the benefit of working if the application doesn't follow XDG spec thanks
to --persist=.local/state.
This fixes https://github.com/flatpak/flatpak/issues/4477
[smcv: Don't call nonexistent g_get_user_state_dir(); fix a reference
to XDG_STATE_DIR]
