🚀 Enhancement: Subcollection Support

[Rizzist]

🔖 Enhancement description

Create subcollection & have appwrite automatically handle it under document such as:

• deleting doc w/ subcollections deletes all subcollections
• reading subcollection by going through doc

🎤 Pitch

Capture Market making it Easier to migrate from ###### Firebase

👀 Have you spent some time to check if this issue has been raised before?

• I checked and didn't find similar issue

🏢 Have you read the Code of Conduct?

• I have read the Code of Conduct

[stnguyen90]

@Rizzist, thanks for creating this issue! 🙏🏼 Appwrite's collections are flat so we typically handle related data via a separate collection. We also support relationships, but they are experimental and should be used with caution as they can lead to performance problems.