Common tree insert function for QUIC and UDP connections. Previously, ngx_udp_rbtree_insert_value() was used for plain UDP and ngx_quic_rbtree_insert_value() was used for QUIC. Because of this it was impossible to initialize connection tree in ngx_create_listening() since this function is not aware what kind of listening it creates. Now ngx_udp_rbtree_insert_value() is used for both QUIC and UDP. To make is possible, a generic key field is added to ngx_udp_connection_t. It keeps client address for UDP and connection ID for QUIC.

--- a/src/event/quic/ngx_event_quic.h
+++ b/src/event/quic/ngx_event_quic.h
@@ -111,8 +111,6 @@ struct ngx_quic_stream_s {
 
 
 void ngx_quic_recvmsg(ngx_event_t *ev);
-void ngx_quic_rbtree_insert_value(ngx_rbtree_node_t *temp,
-    ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
 void ngx_quic_run(ngx_connection_t *c, ngx_quic_conf_t *conf);
 ngx_connection_t *ngx_quic_open_stream(ngx_connection_t *c, ngx_uint_t bidi);
 void ngx_quic_finalize_connection(ngx_connection_t *c, ngx_uint_t err,