MEDIUM: connection: replace idle conn lists by eb trees

The server idle/safe/available connection lists are replaced with ebmb-
trees. This is used to store backend connections, with the new field
connection hash as the key. The hash is a 8-bytes size field, used to
reflect specific connection parameters.

This is a preliminary work to be able to reuse connection with SNI,
explicit src/dst address or PROXY protocol.
diff --git a/src/mux_h1.c b/src/mux_h1.c
index ab639c6..517e358 100644
--- a/src/mux_h1.c
+++ b/src/mux_h1.c
@@ -2828,7 +2828,7 @@
 	 */
 	conn_in_list = conn->flags & CO_FL_LIST_MASK;
 	if (conn_in_list)
-		MT_LIST_DEL(&conn->list);
+		conn_delete_from_tree(&conn->hash_node);
 
 	HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
 
@@ -2848,9 +2848,9 @@
 
 		HA_SPIN_LOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
 		if (conn_in_list == CO_FL_SAFE_LIST)
-			MT_LIST_ADDQ(&srv->safe_conns[tid], &conn->list);
+			ebmb_insert(&srv->safe_conns_tree[tid], &conn->hash_node, sizeof(conn->hash));
 		else
-			MT_LIST_ADDQ(&srv->idle_conns[tid], &conn->list);
+			ebmb_insert(&srv->idle_conns_tree[tid], &conn->hash_node, sizeof(conn->hash));
 		HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
 	}
 	return NULL;
@@ -2946,7 +2946,7 @@
 		 * to steal it from us.
 		 */
 		if (h1c->conn->flags & CO_FL_LIST_MASK)
-			MT_LIST_DEL(&h1c->conn->list);
+			conn_delete_from_tree(&h1c->conn->hash_node);
 
 		HA_SPIN_UNLOCK(IDLE_CONNS_LOCK, &idle_conns[tid].idle_conns_lock);
 	}