OpenConfig: QoS classifier, rewrite, and scheduler

This feature includes support for QoS classifier, rewrite and scheduler OpenConfig configurations and state sensors using Junos telemetry interface (JTI). This feature includes support for term ID for Classifiers, Differentiated Services Code Point (DSCP-SET) for IPv4 and IPv6 behavior aggregate (BA) classifiers. The feature also supports term ID for rewrites and the sequence ID and burst size for scheduler maps.