rev-models - Possible New Features

[dupski]

• ReadOnly fields (for calculated fields)
• FieldResolvers for looking up related or summary fields - in registry meta
• RelatedRecord and RelatedRecordList fields [DONE[
• Support a 'fields' option to read() a subset of fields
• group_by?
• Hooks (beforeCreate, afterCreate, beforeUpdate, etc) - in registry meta