Add support for JSON batching

[rikkuness]

It would be really awesome if we could add support for JSON batch requests https://docs.microsoft.com/en-us/graph/json-batching.

Although I'm really not sure the best way to cleanly integrate it here especially if batching multiple different request types and then mapping the responses appropriately. I don't mind having a poke around to see if it's possible given a consensus it would be a beneficial feature to have.

[manicminer]

Hi @rikkuness, thanks for requesting. Whilst this isn't something I can work on as a priority, I'd be open to adding it if you'd like to try out some potential implementations. You've highlighted the challenges, perhaps as a first pass, batching requests on the same object type would be a simpler place to start.