Redundant documentation for measure, data, data type, and sampling scheme

[Whathecode]

• Methods which return a measure need to document what to measure.
• They contain a data type which needs to document what corresponding data represents.
• The data classes themselves need documentation.
• The associated sampling schemes, which for now are closely linked to data types (https://github.com/cph-cachet/carp.core-kotlin/issues/170), also need documentation.

All of this is very redundant documentation, even though the context for each is slightly different and having documentation is still highly relevant given that these are part of the public API.

Can we instead generate documentation for these?

[Whathecode]

Since, specializations of measure have been removed, so the duplication is reduced slightly.