🚀 Enhancement: How do Chinese developers add local push notification providers?

### 🔖 Enhancement description Added push notification providers available in China. ### 🎤 Pitch As we know, FCM is unstable in China.Is it possible to connect to a Chinese push notification provider, or customize your own provider? ### 👀 Have you spent some time to check if this issue has been raised before? - [x] I checked and didn't find similar issue ### 🏢 Have you read the Code of Conduct? - [x] I have read the [Code of Conduct](https://github.com/appwrite/.github/blob/main/CODE_OF_CONDUCT.md)