[Help wanted] Translate 'file-backup' function from Python to PHP 👨🏾‍💻

[Glide7]

Translate 'file-backup' function from Python to PHP 👨🏾‍💻

We use Appwrite Cloud Functions demos as a good way to show how Cloud Functions can be used with Appwrite, and also as a good starting point for developers wanting to write their new functions.
Help us translate the cloud function 'file-backup' from Python to PHP ☁

Requirements 🔎

• For testing your code, you need a running Appwrite instance with cloud functions enabled. You’ll need to setup Appwrite from source using the 0.7.x branch and Docker. 🐳
  Clone the appwrite/appwrite 0.7.x branch. More instruction about how to start your Appwrite server from source are available here. 💻

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If this is your first PR for Appwrite, it is best to read some of our contributions guidelines.
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For each target language we provide with a template for starting a new function. For PHP you can use this template as your starting point. 🥰