CoS with Segment Routing for IPv6

We support CoS with Segment Routing for IPv6 (SRv6) to combine traffic prioritization and efficient routing. This enables better resource allocation and enhanced quality of service, resulting in a more reliable and responsive network. By default, we support uniform mode for CoS propogation, where the inner CoS value is propogated to the outer IPv6 header, that is, the SRv6 tunnel, for both classic and micro-SID (uSID) scenarios. CoS is also supported with the flex-algo SRv6 tunnels and the Segment Routing for IPv6-Traffic Engineering (SRv6-TE) tunnel.