EVPN-Specific BMP RIB Statistics Extensions

This document defines new EVPN-specific BGP Monitoring Protocol (BMP) statistics types. These extensions include scalar counters for EVPN route types specifically, while also keeping scope for defining counters which are EVPN route-type agnostic but related to BGP-EVPN RIB like, number of multihoming Ethernet Segments, number of multihomed EVIs, number of aliased paths, number of dynamic inter-VRF route leaking (IVRL).