controller: allow markers and packet filters on Ethernet switch links

The brctl Ethernet switch runs a per-port uBridge relay, so it can host
the mark filter and packet filters like any uBridge-backed node. Add
ethernet_switch to _MARKER_CAPABLE_TYPES and _get_filter_node, narrow the
UDPLink.update() NIO-PUT skip down to the Dynamips-hosted ethernet_hub,
and expose the matching compute endpoints: PUT nio (filter/marker
reapply) plus the per-marker toggle/pause/resume/delete/rebuild routes.

The ethernet_hub keeps its exclusion: its routes still wire into the
Dynamips hub, which has no uBridge of its own.

gns3server/controller/link.py

@@ -624,6 +624,8 @@ class Link:
                 "nat",
                 "virtualbox",
                 "docker",
+                # the brctl Ethernet switch applies filters on its per-port uBridge relays
+                "ethernet_switch",
             ):
                 return node["node"]
         return None