Additional sensor support for oc-aft streaming of FIB telemetry

This feature extends OpenConfig Abstract Forwarding Table (oc-aft) based streaming of forwarding information base (FIB) telemetry to support specific leaves under IPv4-unicast, IPv6-unicast, next-hop-groups, and next-hops containers. The support is based on the OpenConfig data model openconfig-aft.

You must meet the existing requirements to stream telemetry data and also include the oc-tlv statement at the [edit routing-options forwarding-table] hierarchy level to enable statistics collection.