Sample data now has submits_for referenced by name, convert it to a uuid in principals tests.
The serializing validator is not currently thread safe.
Add a permission validator
Fix dbxref definition in target schema.
Hook up more schemas
General fixups; Handle user/lab circular references.
pi link type should be user
Use lab title as key for now as that's what the spreadsheets have.
Update fixture to account for test data keys
mixinProperties for shared schema properties.
aliases -> separate lot_id_alias / product_id_alias for now to match the sheet.
Embed document in validation
More keys
various