bookTicker Data Missing Since March

[aleexharris]

It appears as though bookTicker data has stopped being offered and it would be great to see this make a comeback.

The last bookTicker daily data for BTCUSDT was in March earlier this year and for other symbols its even older than that. Furthermore, this data was only offered for Futures products and not Spot.

I can see not only myself, but also others asking to see this data being offered again for Futures, as well as making it available for Spot.

Other issues on the topic:
#371
#315