Set iBTC issuance fee to 0.1% and redeem fee to 0.1%

Set the iBTC issuance fee to 0.1% of the BTC deposit and iBTC redeem fee to 0.1% of the BTC being withdrawn. So if you issued 1.0 BTC then you'd pay an issuance fee of $55 (at $55k/BTC)

Historical Background:

Originally, Interlay iBTC fees were set to 0.15% for issues and 0.5% for redeems. Then in Interlay ref 58 in June 2023 the fees were dropped and griefing collateral slashed as an experiment to see if it would increase bridge usage by making it easier and more attractive for people to bridge their BTC.

However, what we've usually seen recently is an over-usage of the iBTC bridge. Specifically there is always very high demand for iBTC but this hasn't translated into more collateral being deposited and more vaults operated (currently at ~20% APR).

Competitor Comparison

Threshold (tBTC) on Ethereum has 0.1% issuance and used to be 0.2% redeem but I think more recently removed that for some reason. source: https://hackmd.io/@LlamaRisk/tBTC

Community voting:

The Interlay community voted in a straw poll in Discord, with 11 voters. The issue/mint fee has an average of 0.091% and clear voter preference for 0.1%. The redeem/withdraw fee was still very split with an average of 0.086%. Therefore I am submitting this proposal for both the iBTC issue and redeem fees to be set at 0.1%.

Compensation requested for competitive research, community discussions, chopsticks testing, proposal creation. 5hrs x $100/hr = $500 = 30,940 at $0.01616/INTR.