local-node: handle BSS transition queries

Make usteer handle incoming BSS-transition requests. Update with the
most active roaming neighbors like we already do for imminent
disassociations.

Create a new ubus method which calls hostapds bss_transition_request
method. This does not set the disassoc imminent bit, thus will not
automatically disassoc the requesting STA.

Signed-off-by: David Bauer <mail@david-bauer.net>

node.h

@@ -53,6 +53,9 @@ struct usteer_local_node {
 
 	struct kvlist node_info;
 
+	struct uloop_timeout bss_tm_queries_timeout;
+	struct list_head bss_tm_queries;
+
 	struct {
 		bool present;
 		struct uloop_timeout update;