Add gitignore section for library binaries before copy

adds gitignore section to ignore library binaries before they are copied
from bin/<platform>/* to project/bin/<platform>/*

.gitignore

@@ -3,20 +3,10 @@
 .godot/
 
 # Ignore library files but not the gdextension file
-project/bin/*
+/bin/**
-!project/bin/android
-project/bin/android/*
-!project/bin/android/.gitkeep
-!project/bin/linux
-project/bin/linux/*
-!project/bin/linux/.gitkeep
-!project/bin/macos
-project/bin/macos/*
-!project/bin/macos/.gitkeep
-!project/bin/windows
-project/bin/windows/*
-!project/bin/windows/.gitkeep
 !project/bin/*.gdextension
+
+# Ignore scons database
 .sconsign*.dblite
 
 # Ignore custom.py