Data_object should get a status attribute

[Stroomversnelling]

Is your feature request related to a problem? Please describe.
You should be able to quickly select devices that are still actively generating data.

Describe the solution you'd like
Data_object should get a status attribute

Describe alternatives you've considered
N/A

Additional context
N/A

[nickdickinson]

Will it be sufficient to do what we proposed in #7 and simply add a start and end date to each data_object so it is clear which is active. Or is this about devices temporarily not providing data? Please clarify.

[Stroomversnelling]

I believe this is fixed, but will await confirmation before closing.