Align the multi_xxx calls with the rest of the sdk

We should accept the corresponding Options, in those calls, rather than just the old-style kwargs. For instance, multi_upsert should accept an UpsertOptions object, etc... That way, the options are really documented. It could be there are some differences – perhaps some options are not really passed on, but AFAIK, there are none. If so, we could make their own Options classes.

Alternatively, we can continue to accept the kwargs, but document what is actually accepted (like span).