Should the column name/alias be required in the base ViewDefinition or in a new ShareableViewDefinition profile?

[rbrush]

From the Zulip discussion at https://chat.fhir.org/#narrow/stream/179219-analytics-on-FHIR/topic/Column.20name.20when.20not.20specifying.20.60alias.60, we have rough consensus that the column name/alias must be defined for a view to be shared or reused.

This leads us to the question of whether it should be required in the base ViewDefinition, or in a new "ShareableViewDefinition" profile that adds this constraint.

[jmandel]

I think we're getting ahead of ourselves with profiling. I think we should be okay with having it required in our model while also recognizing that some tools might be able to auto populate it or infer it.