Add support for Hangouts Meet

[timbroder]

https://gsuite.google.com/learning-center/products/meet/get-started/#!/

This currently can't be done as far as I can tell, but if I can figure it out, I'll submit a PR. The meeting IDs aren't arbitrary, so just crafting a url won't work. Currently, you'd have to go in through the calendar api and create an event at the same time.