Add rollingsum filter for frame analysis based on column mean deviation

- Implements GStreamer element that analyzes pixel columns
- Drops frames when column mean deviates from rolling baseline
- Configurable window size, column index, stride, and threshold
- Includes design documentation and build script
- Tested successfully with IDS uEye camera source

gst/CMakeLists.txt

@@ -10,5 +10,6 @@ if (ENABLE_KLV)
 endif ()
 
 add_subdirectory (misb)
+add_subdirectory (rollingsum)
 add_subdirectory (select)
 add_subdirectory (videoadjust)