Add get_utilization_ratio to rust sdk

[DannyDelott]

LPs want to know their ratio of idle capital to capital that is being used to back open positions. The calculation for this current lives in React and looks something like this:

// pseudo code
// grab the number of withdrawal shares received from a preview max remove liquidity call.
const { proceeds: unusedProceeds, withdrawalShares } = previewRemoveLp(balanceOfLpShares);
const utilizationRatio = (withdrawalShares / balanceOfLpShares) * 100;

https://github.com/delvtech/hyperdrive-frontend/blob/48280bb6a12528b11e17c45612fc1fdab3cdd4c2/apps/hyperdrive-trading/src/ui/hyperdrive/lp/hooks/useUtilizationRatio.ts#L7