Refactor GDScript/C# script templates logic to be editor-only

Not a full refactor as it still goes through ScriptLanguage so it's hacky,
but at least it can now compile without this.

modules/gdscript/editor/script_templates/Node/default.gd

@@ -0,0 +1,13 @@
+# meta-description: Base template for Node with default Godot cycle methods
+
+extends _BASE_
+
+
+# Called when the node enters the scene tree for the first time.
+func _ready() -> void:
+	pass # Replace with function body.
+
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta: float) -> void:
+	pass