Added import and export for the level designer

ImportPanel.gd

@@ -0,0 +1,18 @@
+extends PanelContainer
+
+signal object_imported(data : Dictionary)
+
+func show_panel() -> void:
+	$VBoxContainer/ImportedCode.text = ""
+	$VBoxContainer/ImportedCode.grab_focus()
+	visible = true
+
+func _on_import_pressed() -> void:
+	var text = Marshalls.base64_to_utf8($VBoxContainer/ImportedCode.text)
+	var ob = JSON.parse_string(text)
+	if ob != null:
+		object_imported.emit(ob)
+		visible = false
+
+func _on_cancel_pressed() -> void:
+	visible = false