Listings updates

- event no longer provide a dedicated venue. This is achieved through
the showtime record
- The concept of a “primary” venue has been removed
- Cinema listings have been simplified
- Re-worked event transformer to utilise different data based on the
event type
- ShowTimeTransformer re-worked to gather show data more clearly.
- Removed several unwanted attributes
Putting back removed attributes with null values

- adding in previously removed fields so to not break the
implementation on devices.
Merge branch 'listings-rework' into dev