Improvements for local network spinning up script

[shimkiv]

• The real issue we address here is the way of genesis_state_timestamp updating.
  • Using previous date-time formatting string %Y-%m-%dT%H:%M:%S.%6NZ (time-zone specifically) is not acceptable by Node at least on macOS (on compatible and develop branches).
• BREAKING CHANGES introduced, hence, targets develop:
  • The ledgerfolder default path was changed in order to preserve work-dir after the OS restart.
• Everything else is just a usability/cosmetic improvements.
• The -generate-genesis-proof Daemon's CLI arg was removed since it was deprecated;
• Fix bug with reset=false option in order to prevent the work-dir cleaning up between scrip restarts.