Store whether or not data type pertains to a participant

[Whathecode]

Data points have an optional 'participation ID'. This does not need to be set when the data pertains to e.g., the weather, or smart home sensors (cupboard closed). But, it needs to be set if the data pertains to a participant, e.g., stepcount.

To enable validation in the infrastructure whether or not a data point is valid, it is relevant to know whether or not data is expected to pertain to a participant.

This might be relevant to store in DataTypeSamplingScheme.

[Whathecode]

This could in fact be specific to instances of sampling schemes. For example, while geolocation on a smart phone might pertain to a participant, it does not necessarily pertain to a participant in the case of a moving beacon (e.g., to track the movement of an object in a home).

[Whathecode]

The participantId was omitted from data points when the data subsystem was added to carp core.

However, currently, I am in the process of introducing "participant roles" to study protocols. If we end up inviting participants to take part in a study, they could be invited to use the same device. In that case, it could be useful to associate the participant role that is currently using the device to the data points.

This is not a common scenario we intend to support right now, but this issue may become relevant in the future.