Add optional link to Device in ImageSeries

[rly]

Motivation

Support NeurodataWithoutBorders/nwb-schema#454

Requires NeurodataWithoutBorders/nwb-schema#454 to be merged

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[bendichter]

what about the descendants, TwoPhotonSeries and OpticalSeries? Will they support devices?

[rly]

Thanks. I just added that. I also added it in ImageMaskSeries which is the other subclass of ImageSeries because based on the schema you can have an optional link to a Device in a ImageMaskSeries. It doesn't really make sense to, but currently we have no way in the schema to say that an optional link in a parent type is not allowed in the child type.

[rly]

I guess since it doesn't make sense to have a separate link to a Device in ImageMaskSeries, we can restrict that in the API. It depends on whether we want the API to support the full flexibility of the schema or not.

[bendichter]

If we leave it out, then it won't be supported on read, will it? I think if someone creates a file that NWB supports, we should be able to read it. We can use the doc of that arg to say that this field would likely not be needed.

[rly]

Right, if we leave it out, it would not be supported on read. Good point

[oruebel]

Removing/hiding attributes inherited from a parent type should not be allowed. If an attribute on a parent class does not make sense in a child class then that typically points to problem in the model.