XDM V1 Message Format

[vedhavyas]

We have an audit issue #2439 where our current V0 message format uses constant Weight to Fee conversion instead of Adjusted Weight to Fee.

Adjusted Weight to Fee conversion uses TransactionPayment::next_fee_multipler so that fee is dynamic. We also want to remove the relay fee and instead use a fee multiplier so that it can cover fees on both src and dst chain as the both chains will lead to different adjusted weight to fee multipler.

Below is the outlined migration path for Taurus. For mainnet, there are no domains to migration is not required

• Include new V1 message format, Fee Multipler, and Adjusted Weight to Fee Conversion but continue using V0 message format #3446
• Upgrade runtimes, both Consensus and Domains
• Once the runtimes can handle V1 format, Start using new V1
• Upgrade runtimes so that they can start using V1 formats
• Cleanup the V0 message format