Replace request fees

[nud3l]

Is your feature request related to a problem? Please describe. Replace requests are free. This works alright for the fee model where vaults get more rewards when they have more BTC locked (as they have an incentive to get more BTC locked) but does not work well with the capacity model.

Describe the solution you'd like Similar to issue and redeem, as a volume-based replace fee that gets paid form the oldVault to the newVault.