Clearing cache (and IndexDB) is required when switching networks/contracts

[phutchins]

In development when changing the grantRegistry and grantRoundManager contract addresses (in chains.ts) you must clear cache and clear the IndexDB in order to see the correct grants. This should happen automatically. I.E. we could keep the other cached data but index new data under a new key and point to the appropriate set of data depending on contracts being used.