/channels/:id/aggregated_metrics response format

1. main response

[
  {
    "tags": {
      "org_id":           <org id>,
      "channel_id":       <channel id>,
      "top_cards":        [<top cards records>...],
      "top_contributors": [<top contributors records>...],
      "top_scoring_users: [<top scoring user records>...],
    },
    "values": [<channel aggregation records>...]
  }
]

2. top cards record

{
  "title":               <string>,
  "card_id":             <int>,
  "organization_id":     <int>,
  "sum_num_likes":       <int>,
  "sum_num_views":       <int>,
  "sum_num_completions": <int>,
  "sum_num_bookmarks":   <int>,
  "sum_num_comments":    <int>,
  "sum_num_assignments": <int>,
  "sort_score":          <int>
}

Note:
- All the integers here represent sums over the date range requested
- "sort_score" is the sum of the 6 other integer columns
- These records are ordered by "sort_score" descending

3. top contributors record

{
  "first_name": <string>,
  "last_name":  <string>,
  "user_id":    <int>,
  "bio":        <string>,
  "num_cards":  <int>
}

Note:
- the "num_cards" here is the sum for the date range requested

4. top scoring user record

{
  "first_name":       <string>,
  "last_name":        <string",
  "user_id":          <int>,
  "bio":              <string>,
  "total_user_score": <int>
}

Note:
- the "total_user_score" here is the sum for the date range requested

5. channel aggregation record

{
  "time":                                      <string, start of the day for this record>,
  "num_monthly_active_users_total":            <int>,
  "num_monthly_active_users_in_web_platform":  <int>,
  "num_monthly_active_users_in_null_platform": <int>,
  "num_channel_visits":                        <int>,
  "num_channel_follows":                       <int>,
  "num_cards_added_to_channel":                <int>,
  "num_cards_removed_from_channel":            <int>,
  "num_cards_liked_in_channel":                <int>,
  "num_cards_commented_in_channel":            <int>,
  "num_cards_completed_in_channel":            <int>,
}

Note:
- These are NOT summed for the entire date range. For example, if send a request with params
  start_date=<10 days ago> and end_date=<now> then you will get 10 of these records, one for each of
  the 10 days in the range.