NEB: fix handling of pre-event loop logs (at least).
NEB: fix handling of pre-event loop logs (at least).

When Broker started, all initialization was made upon the
event-loop start callback. However, some logs were emitted before
this event. Now configuration loading is made at process startup
and initial objects dump is made at the event-loop start.

This fixes #4253.

centreon/centreon-broker,centreon/centreon-broker,centreon/centreon-broker,centreon/centreon-broker,centreon/centreon-broker