Use MaxCollateralUtilization or MinCollateralLiquidity in interest rate calculation

[robert-zaremba]

Depends on:

• Add MaxCollateralUtilization or MinCollateralLiquidity to Token Registry #1036

Summary

In #940 we introduced MaxCollateralUtilization and decided to use it for interest rates instead for supply utilization.

• update algorithm
• update tests
• make sure borrows are not possible if collateral utilization goes above max collateral utilization

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[toteki]

This can be closed - interest rates will still be based on borrow utilization, not collateral utilization.

Even assets with collateral weight = 0 (cannot be collateralized) need dynamic interest rates.

[robert-zaremba]

Today we have supply_utilization not borrow_utilization.

I think we should consider changing interest rates base on borrow_utilization (the new model)