Adds Poisson blending

- adds poisson blending on the face to make a seamless blending of the face and the swapped image removing the "frame"
- adds the switch on the UI

Advance Merry Christmas everyone!

modules/globals.py

@@ -27,6 +27,7 @@ keep_audio: bool = True
 keep_frames: bool = False
 many_faces: bool = False         # Process all detected faces with default source
 map_faces: bool = False          # Use source_target_map or simple_map for specific swaps
+poisson_blend: bool = False      # Enable Poisson Blending for smoother face swaps
 color_correction: bool = False   # Enable color correction (implementation specific)
 nsfw_filter: bool = False