Option to set dynamo db table capacity mode to 'on-demand'

[Duanne-IAG]

Describe the outcome you'd like
Ability to set capacity mode of ddb tables to 'on demand'/'pay per request'

A clear and concise description of what the problem is.
We have over 640 accounts managed by aft in our organisation. Prior to provisioning new accounts, we run a tf plan to ensure that the account request is unique. This plan queries the 'aft-request' table and takes 10 minutes on average for a mere tf plan because the table only has 1 RCU. When changing it to 'on-demand' it takes around 1 minute.
However because this change is not in code, it gets reverted each time a change is made to our aft module, and capacity mode can only be changed once in 24 hours, so manual changes aren't a reliable stop gap either. Considering there a few updates/new requests daily, this adds up to a lot of time not being saved weekly.