Fee Design for Arbitrary Call BSH about btp-product HOT 1 OPEN

There should be two fees assessed on all BTP messages:

Relay Fee - goes to the relay that processed the message
Protocol Fee - goes to FeeAggregatorSCORE

Prior to having the relay network, the single Relay will set the fee in the BMC (or should it be per BSH? Not sure what is best from an architecture standpoint). This fee will be adjustable by the Relay at any time.

When we migrate to a Relay Network, allow relayers to register a message-processing fee directly into the BMC (or maybe BSH?). Cheapest offering should get first opportunity to process the message, but lets discuss the simplest development path.

The Protocol Fee should be set by the contract deployers, eventually moving to a decentralized governance mechanism. It should also be a fixed fee. We can set it depending on the network, then adjust as necessary

from btp-product.