Exposing chain specific logic to the app interface function is bad

Change introduced here: !149 (diffs) requires to know at HAF application side when give HF passed. Such informations should be not exposed to the API offered by HAF.

Probably best option is to hold in HAF database currently information (generated by sql_serializer) related to currently applied hardfork. Then we can introduce 2nd function (Postgres allows names overloading), which automatically reads information related to applied HF and passes it to the actual function.