enhancement: add wallet balance to logs

[danbryan]

I think it would be helpful to see the wallet balance in the logs.
Maybe something like append balance=5000ukuji to Msg("broadcasting pre-vote")

It could either do a q bank balance before every pre-vote or maybe it could be stored in a db and calculate the balance based on number of txs, with some condition to sanity check the balance after X calculations.

Something like this...

9:21PM INF broadcasting vote exchange_rates=10.206124343999644732ATOM feeder=kujira... module=oracle validator=kujiravaloper...
9:21PM INF successfully broadcasted tx module=oracle_client tx_code=0 tx_hash=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA tx_height=0
9:21PM INF broadcasting pre-vote feeder=kujira... hash=aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa module=oracle validator=kujiravaloper... balance=5000ukuji
9:21PM INF successfully broadcasted tx module=oracle_client tx_code=0 tx_hash=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA tx_height=0
9:21PM INF skipping until next voting period current_vote_period=160998 module=oracle previous_vote_period=160998 vote_period=14

Or if the balance is low cfg.Account.balance_threshold do a WARN