Request batching

Currently you're requesting in batches of 5...
https://github.com/hackclub/arrpheus/blob/dc8235b880f03ed116a80cc2d623fd51840fe3c6/src/index.ts#L90

Then also checking for joins in batches of 1...
https://github.com/hackclub/arrpheus/blob/dc8235b880f03ed116a80cc2d623fd51840fe3c6/src/index.ts#L109-L118

Then checking for users in batches of 1...
https://github.com/hackclub/arrpheus/blob/dc8235b880f03ed116a80cc2d623fd51840fe3c6/src/index.ts#L124-L127

And updating the records in batches of 1...
https://github.com/hackclub/arrpheus/blob/dc8235b880f03ed116a80cc2d623fd51840fe3c6/src/index.ts#L136-L144

This means every 30 seconds we have 4 requests made per user invited, and it linearly increases! We can really cut down on that by batching in groups of 10 records at once, which airtable still treats as a single request.