Fix of the issue 46 to retry the connection to the database when the server is unavailable.
Adding the dbConfig property to let users pass their own options to the mongo driver. The actual behavior merges the default dbConfig properties with the one passed in parameters to Krypton. User properties override the default ones.
dbConfigproperty to let users pass their own options to the mongo driver. The actual behavior merges the defaultdbConfigproperties with the one passed in parameters to Krypton. User properties override the default ones.