netlab 26.07: GRE, Wireguard, Graceful Restart, and Scale-Out Labs

The highlights of netlab release 26.07 include: The multiserver plugin by @muddyblack distributes containerlab devices across multiple servers. The GRE tunnel plugin supports GRE tunnels on Cisco IOS, FRR, VyOS, and Junos (vSRX and vJunos-router) (most device implementations done by @ssasso and @jbemmel ). The WireGuard tunnel plugin by @jbemmel supports WireGuard tunnels on FRR. The bgp.session…