Adapt to new code ID discovery

[abefernan]

With the implementation of this tfi functionality (confio/tfi#81) the app should query the code IDs for CW20 and Trusted Token, instead of relying on hardcoded config

[maurolacy]

Just to be clear: Even without this functionality, the app can query tfi-factory (using the Config query) to get the code_ids of token and trusted_token.

What confio/tfi#81 will allow is delegating the creation of these tokens to tfi-factory.

[abefernan]

Ah, I understand. But the reason we'd want that is to use the same admin address as pair creation, set during factory instantiation, no? I'm not sure if any contract that uses other contracts should expose all the functionality from the inner contracts. Maybe we can just expose the admin address from the factory? Not sure