Support buildReference for one-to-many relationships

[mikkopaderes]

Spin-off from the discussions in #150

User Story:

As a user, I want to support buildReference on a one-to-many relationship, so that I can choose to save my records under any collections/sub-collections

Acceptance Criteria:

• Support buildReference on hasMany one-to-many relationship type
• Support buildReference on belongsTo relationships
  • This is only used for determining what collection/sub-collection this relationship will use when saving the Reference data type property.
  • When fetching the relationship, it will bypass the buildReference and simply fetch whatever the Reference data type resolves to