Merge branch 'pppoe-rewrite' of https://github.com/c-po/vyos-1x into current

• 'pppoe-rewrite' of https://github.com/c-po/vyos-1x: (23 commits) pppoe: T2055: do not try to start a deleted dialer interface pppoe: T1318: declutter name-server CLI nodes pppoe: T2055: remove router-advert node in client interface pppoe: T1318: migrate user-id and password nodes under an authentication node pppoe: T1318: rename link to source-interface pppoe: T1318: use include files for disable and descriptionx pppoe: T1318: rephrase help text on default-route interface-definitions: include: disable: rephrase help text pppoe: T1318: extend migrator for firewall, qos and ip routing nodes pppoe: T1318: proper delete old interfaces in migrator pppoe: T1318: increase priority so PPPoE is run after bond interfaces pppoe: T1318: fix migrator and add missing link statement pppoe: T1318: use lists rather then strings on Config() pppoe: T1318: support interface description pppoe: T1318: remove obsolete ipv6-up.d script pppoe: T1318: add op-mode commands for link information pppoe: T1318: use systemd to manage connection pppoe: T1318: remove process startup debug output pppoe: T1318: move process startup to apply() pppoe: T1318: "link" option is mandatory ...