Provide ability to force a capture method via configuration. (#1063)

Co-authored-by: KuleRucket <luke.d.tucker@gmail.com>

src/config.h

@@ -52,6 +52,7 @@ struct video_t {
     int vt_coder;
   } vt;
 
+  std::string capture;
   std::string encoder;
   std::string adapter_name;
   std::string output_name;