Replace RemoteImage.swift with AsyncImage (Xcode 13, Swift 5.5)

Starting with Xcode 13 and Swift 5.5, Apple introduces a command to download images from url for SwiftUI. This command will be possible to run for devices with iOS 15, iPadOS 15 and macOS Monterey or later.

With the use of AsyncImage we can remove the long and painful solution introduced with RemoteImage.swift