Add Transformations for generating Account Stats per Day|Week|Month reports for Facebook Ads
This MR adds transform models for generating Account Stats per Day, Week and Month.
The transformations include the most important metrics for Facebook Ads data:
- impressions
- reach,
- frequency
- clicks
- spend as spend
- cpc
- cpm
- ctr
- results
- results_from_clicks
- cost_per_result
Closes #10 (closed)