[FEATURE] Add Miimon linux bonding metrics

[JustHumanz]

Add :

# HELP node_bonding_miimon MII link monitoring frequency in milliseconds.
# TYPE node_bonding_miimon gauge
node_bonding_miimon{master="bond0"} 200

From

/sys/class/net/<bonding>/bonding/miimon

pr context:

• feat: Add miimon on linux bonding #3319

[SuperQ]

While it's not exactly in scope for this, we really should refactor this collector to use https://github.com/prometheus/procfs.