Api cleanups for device querying

Api cleanups for device querying

Instead of having separate methods for asking the list of device-datas
stored to save directory and list of devices active, only one list of
devices is now returned which compines active devices and list of
inactive devices which have anyway data. Device has now lifecycle state
which indicates whether it's active.

Signed-off-by: Mika Laitio <lamikr@pilppa.org>