Generalize ancillaryResults and qualityMeasures to all Study Results

[mbrush]

Per review with @afrubin on MaveDB.

Originally posted by @ahwagner in #234 (comment)

See also Issue #144 relevant to this topic.

[mbrush]

Responses from original post:

from afrubin:

This will be a very useful way to communicate relevant values like experimental variability (variance, std error) without being overly prescriptive. Having similar naming conventions/structures across GKS Study Results will also make it easier for implementers and data consumers.

From mbrush:

Agree with the utility of a way to capture this type of information in a consistent way, and agree that if we stick with this pattern as a way to capture additional data items in Study Results, then it makes sense to include them in the generic core model StudyResult class. However, reserving final judgement as I have some questions about the proposed modeling pattern, and how it relates to use and modeling of Extensions. Finally, If we do keep this pattern, I would make the simple change of renaming ancillaryReuslts to ancillaryData - as this object contains additional data items, not additional Study Results.

[mbrush]

See also Issue #144 relevant to this topic.