* update MaximumLimit param to MaximumLimitUSD
* track total borrowed coins in the store
* implement total borrowed coins querier
* add maximum value usd check
* update test suite, add zero coins check
* add test case, update error msg
* max limit in native amount
* remove debug logging
* prepare for master rebase
* master rebase
* fix build
* fix: don't allow denoms other than hard for harvest rewards
* fix: parse cli flags correctly
* fix: convert duration to seconds before calculating time elapsed
* fix: don't distribute rewards before they start or after they end
* fix: return correct message type