Implement cli wallet command/api endpoind to verify that SON network is operating as expected

We need a way to verify that SON network is operating as expected.

This check should be based on verifying that SON status is active, and that SON is sending heartbeats regularly. We can also check last reported deposit/withdrawals. All this should be summed up to something similar to witness participation rate, and SON availability mark, like 100%, 90%, 20%, etc...