CalculateSpotPrice should be fee-less

[sunnya97]

Currently we have two functions: CalculateSpotPrice and CalculateSpotPriceSansFee.

I know, this is using the naming used in the Balancer code, but I think this nomenclature of SpotPrice including fees is quite non-standard in industry and we should it correctly. (Even the balancer docs, define spot price as not including fees: https://docs.balancer.finance/core-concepts/protocol/index#spot-price).

I'd recommend switching:

• CalculateSpotPriceSansFee -> CalculateSpotPrice
• CalculateSpotPrice -> CalculateSpotPriceWithFee.

[ValarDragon]

Thats whats already done in this branch https://github.com/osmosis-labs/osmosis/tree/gamm_updates

[sunnya97]

Closed by 4a5ed58

[sunnya97]

While the lower level unexposed functions were switched, the exposed keeper functions are still CalculateSpotPriceSansFee and CalculateSpotPrice.

See: https://github.com/osmosis-labs/osmosis/blob/main/x/gamm/keeper/swap.go#L238

These should be fixed as well.