gog sheets batch-update --requests-json

I know this was closed in #1103, but I'd like to make a proper pitch. batch-update is better and different vs api call:

• batch-update has a narrow security scope
• batch-update facilitates editing transactions, and acts as a single API request for rate limiting
• batch-update works with safe builds
• api call opens up a can of worms and has to download the entire schema for discovery (slooowwwww)

batch-update is the best, let's do more of that! api call is for desperate agents, no need to go there in this case. I won't bring it up again in either case, just marshaling my arguments here.