Prop 440: Phase out incentives for BUSD

This proposal would wind down all OSMO incentives involving the BUSD stablecoin over the following two weeks.

## Details
On the 13th February 2023, Paxos, the issuer of the BUSD stablecoin, released a statement that they will cease further issuance on the 21st February 2023.

This impacts Osmosis as we have recently voted to recognise BUSD as a stable asset, onboard a Core Stableswap pool containing BUSD, incentivise the BUSD/OSMO pool and bootstrap it by allocating initial liquidity incentives.

While the cessation of issuance is concerning, Paxos have attestations of full backing and intend to support redemption of BUSD until February 2024. Therefore this proposal is not an emergency proposal and will stagger the removal of incentives from BUSD related pools to give users time to unbond.

## Proposed Plan
This signalling proposal lays out the path to removing BUSD incentives and has no direct effect.

At the first routine incentives proposal after passing the following would occur:
* Minimum Incentive allocation to Pool 879 removed (Proposal 426 Reversion), lowering incentives to a standard level for a stable pool.

At the second routine incentives proposal after passing the following would occur:
* Removal of Osmosis Incentives from OSMO/BUSD pool (Proposal 425 Reversion)
* Removal of Osmosis Incentives from USDC/USDT/BUSD pool (Proposal 404 Reversion)
* Removal of BUSD as a Stable asset (Proposal 403 Reversion)

Commonwealth Thread: https://commonwealth.im/osmosis/discussion/9998-busd-wind-down