* first steps to metrics

* next small step

* fixed tests

* added comments

* postponed RouterAccepted and RoutesRejected to next step

* read update counters

* added test

* added missing test file

* Route not used any more

* added metrics for session state and time since establish

* increased test coverage, time since establish impl.

* added prom collector

* added metrics endpoint to BGP example

* added metrics for VRF

* removed commented metrics

* fixed logging inconsistency in example

* Update main.go

* gofmt

* fixed typo

* Add Unregister function to VRF to remove VRF from global registry

* Add test for Unregister

* added unique name for locRIBs

* added VRFs

* added error when no RIB configured in VRF

* vrf unique name ensurance

* fixed examples

* added missing test

* for convenience we provide a default RIB for v4 and v6 on each VRF

* removed debug output in main.go (api is coming)

* also removed debug output from fib example

* removed fib example