Don't refresh gNSBT swap power

I will provide more thinking on the alternative 3 proposed in a previous article

The proposal is, when BR < 1, stop refreshing daily the gNSBT swap power after being used for a swap. This will ensure that whoever wants to do more swaps, he will require to stake more SURF instead. This will create demand for SURF but most importantly, it ensures that after a USDN->WAVES burn, the BR always increases instead of decrease.

In addition, the perspective of recovering (and never go back) will generate additional demand for SURF.

The only possible caveat this measure can generate is, arbing may be slightly discouraged. But at same time, if this happens, depeg can be a bit bigger and arbitrage profit will be bigger and reencouraged. Equilibrium depeg may be a bit bigger than today, but we ensure BR recovering, confidence, and that will also improve repeg.

This measure would be disabled as BR surpasses 1.0. However, when this happens, it is probable that only the swap power of gNSBT that comes from NSBT staking should start to be refreshed. The ones from SURF would never be refreshed. Otherwise, sudden refresh of lot of gNSBT may create some imbalance. This measure for example, will ensure that already spent gNSBT from SURF staking cannot be used again if BR goes slightly to zero again before staked SURF start to be liquidated.