LinkML model to support both the DCA and raw usage in CAVATICA

[lopierra]

• Have biosample, assay metadata, and clinical features available in the LinkML INCLUDE model
• All key data elements, attributes/facets, as required for portal and other downstream services, are captured in the INCLUDE data model
• Ensure data types in the data model cover all data types that are to be submitted for a given INCLUDE data release
• Solidify models for biospecimen & data files