Don't need to re-fetch cToken ID's on every account fetch in user table

[haydenshively]

IDs in the CTOKEN table should be constant. The only time they change is if an asset is added/removed from Compound, in which case we could just restart the code. This means that the user table code can just store a map of cTokenAddresses -> cTokenIDs and reuse it when populating the user table with accounts. This should cut down on CPU usage since there are thousands of accounts, and we'd be using one less database call for each one.