Consolidate ICHI Liquidity

Proposal is to:

• Sunset all existing ICHI pools (ICHI-ETH, oneETH-ICHI, ICHI-oneBTC, ICHI-ETH Uniswap)
• Create a new ICHI-ETH pool on Sushiswap
• Set rewards for the new ICHI-ETH pool to 50% of the total (0.5 ICHI per block)
• Split remaining 50% of total rewards between the other pools

Rationale:

Having liquidity fragmented between 4 pools is counter-productive, and joining them is the obvious solution. The choice of Sushiswap is because they are innovating at a much faster pace than Uniswap thanks to their merger with Yearn, and in order to get ICHI-ETH added to their Onsen program for extra rewards.