Prop 12: Reduce the unbonding time to 301 BTC blocks

This governance proposal seeks to introduce a new version of the x/btcstaking module parameters that 1) reduces the unbonding time of BTC Delegations to 301 BTC blocks and 2) increases the slashing fee of BTC Delegations to 150k satoshi. These changes will only apply for new BTC Delegations. For full details, please check the corresponding forum post: https://forum.babylon.foundation/t/reduce-btc-stake-unbonding-delay-from-1008-to-301-bitcoin-blocks/661