Add CustomizationContext and custom hook

As we want to share customization context between reForis & Plugins

src/index.js

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2019-2021 CZ.NIC z.s.p.o. (http://www.nic.cz/)
+ * Copyright (C) 2019-2022 CZ.NIC z.s.p.o. (https://www.nic.cz/)
  *
  * This is free software, licensed under the GNU General Public License v3.
  * See /LICENSE for more information.
@@ -91,3 +91,9 @@ export {
 
 // Alert context
 export { AlertContextProvider, useAlert } from "./alertContext/AlertContext";
+
+// Customization context
+export {
+    CustomizationContextProvider,
+    useCustomizationContext,
+} from "./customizationContext/CustomizationContext";