[FEATURE] Provide conditions for Datastore updates

[YutaUra]

Dynamodb has a feature called conditional put.
This feature is particularly effective in preventing the updated value from being unintentionally updated with the immediately following value when multiple simultaneous puts are made, thus preventing update conflicts in Dynamodb where no transactions exist. It is possible to safely update data by performing appropriate retries on the API caller's side.

Currently, Datastore does not have this functionality and cannot control the behavior of simultaneous updates.

Provide functions like Dynamodb's conditional put.
Or provide values such as updateAt, version, etc. as conditional_token and accept them at API call time to internally condition that they match.

[WilliamBergamin]

Hi @YutaUra thanks for pointing this out 💯

I've flagged this as a feature request, but it does seem like some backend changes may be needed