Remove KeyType

[augustearth]

KeyType was important for Carnival v0 when there were complex data operations that consumed and produced data tables. With the introduction of the graph in Carnival v1, these operations are done in the graph. KeyType is no longer central and should be removed for simplicity's sake.

There is overlap here with secondaryIdFieldMap of GenericDataTable and MappedDataTable. Like KeyType, the secondaryIdFieldMap was important for data table operations. Because secondaryIdFieldMap depends on KeyType, it is not possible to remove KeyType without removing secondaryIdFieldMap.

[augustearth]

Affected Files

project	filename
clinical	EncounterGroup
clinical	PatientGroup
clinical	OmopVine
clinical	EncounterGroupSpec
clinical	FrequencyMatcher
clinical	FrequencyMatcherSpec
core	DataSetDescriptorGraphSpec
core	CachingVineSpec
core	VineSpec
util	KeyType
util	GenericDataTable
util	MappedDataTable
util	FeatureReport
util	TabularReport
util	GenericDataTableSpec
util	MappedDataTableSpec
util	FeatureReportSpec
util	TabularReportSpec

[augustearth]

• Move FrequencyMatcher from Core to Clinical.

[augustearth]

It turns out that EncounterGroup and PatientGroup rely on KeyType for some core functionality. So, rather than remove KeyType completely, I moved it up to carnival.clinical.util and left it in use by PatientGroup and EncounterGroup. I had already removed it from FrequencyMatcher.... which I suspect is a class that will be rethought anyways.