Make minor updates and corrections to the Data Model

[PhilipMusk]

The data model is in need of some minor updates and corrections:

1. Add demographic_id to the demographic node and mark as a key field to support the almost inevitable updates to existing demographic records
2. Add a statement to the description for the the demographic_id, diagnosis_id and enrollment_id to indicate that the vales for each of these properties will generally be the same as the value of the case_id property
3. Within the study node, confirm that the description for the accession_id property references the purely numerical format rather than the prior alphanumeric format
4. Within the publication node, the publication_title property is identified as a key field, but its description lacks any explanation of the key field concept
5. Within the prior_surgery node, Src for therapeutic_indicator needs to be corrected from "Data Owner" to "Data Owner(s)"
6. Within the study_site node, property descriptions need to end in periods
7. Within the case node, modify the description for the both the case_id and patient_id properties to soften the references to data transformation
8. Within the sample node, Src for summarized_sample_type needs to be updated from "Internally-curated" to "Data Owner(s)"
9. Within the file node, Src for file_size and md5sum needs to be updated from "Data Owner(s)" to "Loader-derived"
10. At the appropriate time, change the value of the Template tag for the file node from No to Yes, in support of the generation of a File Transfer Manifest template per ICDC-2745