Add laser sound effect and implement BigLaser bullet behavior

- Added laserbig.ogg sound effect import configuration.
- Created BigLaser script extending BulletBase with AI targeting and dot application functionality.

resources/sounds/effect/laserbig.ogg.import

@@ -0,0 +1,19 @@
+[remap]
+
+importer="oggvorbisstr"
+type="AudioStreamOggVorbis"
+uid="uid://q65xjxxq1m4j"
+path="res://.godot/imported/laserbig.ogg-c68f8d84676af4ccb64c68f85992ce2d.oggvorbisstr"
+
+[deps]
+
+source_file="res://resources/sounds/effect/laserbig.ogg"
+dest_files=["res://.godot/imported/laserbig.ogg-c68f8d84676af4ccb64c68f85992ce2d.oggvorbisstr"]
+
+[params]
+
+loop=false
+loop_offset=0
+bpm=0
+beat_count=0
+bar_beats=4