Remember community name for OSPF neighbours

When you've multiple SNMP communities it seems that Observium will try all communities every time when it is doing a discovery. This even happens when the neighbour is already known and added as device.

This also creates authentication failure events in the logging on some devices and slows down the discovery dramatically.

So if Observiums keeps track of the community name for the neighbours this will speed up the discovery times and prevents event errors on probed devices.