Previously all of the rows on the recommended tab for Movies & TV Shows
were loaded sequentially before any results were shown. This is not a
great experience because some of the queries (eg top rated unwatched)
can take a while sometimes.
This PR starts displaying content once the first 1 or 2 rows is loaded
and then shows placeholders while the rest are querying.
Finally the row queries are now mostly independent so if one errors out,
the rest of the rows will still be displayed.
Closes#180
98fc996bd5