Preconf RPC improvements: Bundle bids #728
Description
Currently the RPC service sends one bid per transaction that it receives. This can be optimized slightly by sending bundle if we have multiple bids. We will need to ensure the bid amount is correctly charged between the users that are part of the bundle. There is a possibility that the bundle is rejected due to some bid (state contentious txns etc). Need to think about how to handle this in more detail.