Moved the Object classes for bridge Discovery

This is a first step for having a
simple unique object model
used by Enhanced Linkd and
Linkd
Renamed class for checking if vtp is enabled on cisco devices
Moved enlinkd snmp classes to their own package
Added a test for IpNetToMediaTableTracker
The qbridge forwarding table must be walked always

Added Test for Walking Bridge data
Added safe null check for weird snmp agent to fbd classes
Moved all the brudge discovery algorithm to model

The bridgeTopology class has been improved with new checking conditions for finding links
Reworked test for linkd and enhanced linkd

Added test for walker class for enhanced link bridge discovery
Checked the nms4930 net and one link has been found using the bridge alg
Fixed a Typo in comment
Fixing Linkd Tests
Removed unusuful vlan from mac address table
Added test for bridge topology

Step 1 print the topology
Fixed Lonkd Test

This must be reworked
Merge branch 'space/14.1-enlinkd' into space/14.1