[FEATURE] support upsert through the client

[Prophet32j]

Is your feature request related to a problem?

no

What solution would you like?

add an upsert function to go along with create and update

What alternatives have you considered?

N/A

Do you have any additional context?

no

[Prophet32j]

I just now realized after another cup of coffee that the index operation is upsert when an ID is passed. Unless the team wants to explicitly identify the upsert operation I think this can be closed

[dblock]

It's possible that the client could use an explicit upsert method? Or maybe a sample called upsert.js? Want to write one?