New fields for adding metadata to study freezes

[pendingintent]

When creating a freeze or snapshot of a study, this represents a study design. Additional data is required to support USDM definition.

Metadata tied to study designs:
studyType (interventional or observational; select from codelist)
studyPhase (select from codelist)
therpeuticAreas (codelist driven but external, i.e., SNOMED; make it free text for now)
rationale
indications
objectives (endpoints are an element of objectives)
population
subtypes (can be selected from a codelist)
blindingSchema (can be selected from a codelist)

[pendingintent]

Values are al tied to a particular StudyDesign when selecting to create a freeze/snapshot.