Add common interface for network requests

We should decide on whether to use a specific network library (e.g. Ktor? OkHttp?), or to add a common interface for end consumers to implement, something like:

```kotlin
interface HttpClient {
suspend fun request(request: NetworkRequest, block: (NetworkResponse) -> T): T
}
```

https://github.com/coil-kt/coil/blob/main/coil-network-core/src/commonMain/kotlin/coil3/network/NetworkClient.kt for an example