Implement runtime reporting of git version compiled into hivemind source code.

Also I'd like to have reported some version of underlying database (can be the same git revision stored in the database during schema creation). Additionally, hivemind instance shall report its head block (block it is synced up).

All above informations shall be printed at application startup. Also specified command line shall be logged (instead of default option values). Additionally to the hive_api dedictated method get_info shall be added providing the same data in json response.