Database operators support on relationship columns

### 🔖 Enhancement description

Database operators should allow me to update relationship columns.

### 🎤 Pitch

The Array operations look like a great fit for several use-cases on relationship columns.
They could be used to add / edit / remove relationships using the id of the related field.
Here is an example of how it could be used:
```
await databases.updateRow(
databaseId: AppwriteConstants.databaseID,
tableId: AppwriteConstants.tableID,
rowId: id,
data: {
"related": Operator.arrayAppend([related_id])
}
);
```

### 👀 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)