KnowledgeBase models proposal

{
  kb article id: uuid,
  content: [
    {
      id: line uuid
      exists: boolean
      line: string
      lastEdited: {
        at: brigade uuid
        by: user uuid
        on: date
      }
      history: [
        {
          action: string
          previous: string
          new: string
          actor: {
            at
            by
            on
          }
        }
      ]
      flags: [
        {
          by
          at
          on
          reason
        }
      ]
    }
  ]
  created: {
    at: brigade uuid
    by: user uuid
    on: date
  },
  flags: [
    {
      by
      at
      on
      reason
    }
  ]
}

{
  suggestion id: uuid,
  contentChanges [
    {
      kb article id: uuid
      content line id: uuid
      update type: string
      previous: string
      new: string
      context: line above uuid
      flags: [
        {
          by
          at
          on
          reason
        }
      ]
    }
  ]
  actor: {
    at
    by
    on
  }
  flags: [
    {
      by
      at
      on
      reason
    }
  ]
}

{
  comment id: uuid
  body: string
  actor: {
    by
    at
    on
  }
  entity: string kbarticle|kbline|kbsuggestion|kbcomment
  entity id: uuid
  flags: [
    {
      by
      at
      on
      reason
    }
  ]
}