BonFire does not contain Activity

[oksanasalohubova]

Linked with Asses ZenPub replacement with BonFire #121

### Activity We have no way to get Activity in these requests and mutations

query activityPreview($activityId: String!) {
  activity(activityId:$activityId){
    id
  ...ActivityPreview
  }
}

fragment ActivityPreview on Activity {
  id
  verb
  createdAt
  user {
    icon {
      id
      url
    }
    image {
      id
      url
    }
    userId: id
    userName: name
    canonicalUrl
  }
  context {
    ... on Community {
      ...CommunityPreview
    }
    ... on Collection {
      ...CollectionPreview
    }
    ... on Resource {
      ...ResourcePreview
    }
    ... on User {
      ...UserPreview
    }
    ... on Comment {
      ...CommentPreview
    }
    ... on Flag {
      ...FlagPreview
    }
    ... on Like {
      ...LikePreview
    }
    ... on Follow {
      ...FollowPreview
    }
  }
}