GitLab

- Do not rely on local lastTimeSeen and requested fRequested anymore. Use last know (signed) ping instead and base all logic on that. Should reduce mn list difference between
 nodes.
- Rework CActiveMasternode accordingly along with states, errorMessages, rpc etc.
- Clean some related code, move parts from public to private
- drop c_str in LogPrintf that were related to this functionality (todo: drop it for LogPrintf everywhere else)