conf: improve console logging format for journald
conf: improve console logging format for journald

When watching logs via the journalctl tool, the former log message
pattern was sometimes not very useful and duplicating certain
information. Currently, we only log shortened level, the message
and finally the logger name and thread identifiers.

PID, time and hostname are already injected by the journalctl.

Signed-off-by: Jan Viktorin <3eab6ac54c005c4408f608556a6663b7f2abede7@fit.vutbr.cz>

BeeeOn/server,BeeeOn/server,BeeeOn/server,BeeeOn/server