[Convex] vlCVX bounty fee changes

Summary

Lower the bounty for kicking expired locked CVX to 0.25% from 1% of expired locks.

Abstract

The bounty to remove expired locked CVX is intended to stop non-vote participating CVX from receiving rewards intended only for locked CVX. The one percent fee was intended to cover gas costs plus a small bounty for doing so. The Convex Finance team believes lowering the bounty to 0.25% of the expired lock is more in line with the intended function and not a way to extract excess value from the protocol.

The grace period for when the bounty will become available will remain the same at four epochs (weeks). After four weeks, the bounty will be 0.25% of the expired locked CVX, increasing by 0.25% for each epoch after that. For more details on how the current bounty works, please see the documentation at: https://docs.convexfinance.com/convexfinance/general-information/understanding-cvx/vote-locking