Add flexible document store with history to track field changes

[mikesparr]

Many organizations centralize around one or more types of document, or data, but need the ability to monitor edits on a field-by-field basis. Similar to a CRM with customizable contacts, we should include a mechanism for storing documents of multiple types and tracking their changes.

Proposed schema

• id uuid
• type string (use ObjectType enum to validate type)
• properties: {[key: string]: {[key: string]: any} }
  • value any
  • history: Array<{[key: string]: any}> (todo: define PropertyHistory and Property interfaces)
    • oldValue: any
    • newValue: any
    • editor: string
    • timestamp: number (UTC unix time with millis)
• published: string (ISO-8601)
• updated: string (ISO-8601)
• enabled: boolean
• sort: integer

TODO: consider group and user ownership (use graph or just FK columns within: KISS)

Other consideration

• need a Schema entity store to validate dynamic node types
  • use the same structure as DTOs if possible and leverage class-validator