SNMP Bridge MIB support

[troglobit]

Of all things SNMP, the BRIDGE MIB is one of the most useful features.

Some research on this topic:

• https://sourceforge.net/p/net-snmp/patches/1242/
• https://sourceforge.net/p/q-bridge-mib/code/HEAD/tree/
• https://github.com/obliviand/bridge-snmp