Improve RTSP support to configure port and expose low res stream

rtsp/rtsp.h

@@ -1,5 +1,12 @@
 #pragma once
 
+typedef struct rtsp_options_s {
+  uint port;
+} rtsp_options_t;
+
+extern rtsp_options_t rtsp_options;
+
 int rtsp_server();
 bool rtsp_h264_needs_buffer();
 void rtsp_h264_capture(struct buffer_s *buf);
+void rtsp_h264_low_res_capture(struct buffer_s *buf);