Begin work on porting the add feed/folder dialog to SwiftUI

iOS/Add/UIKit/AddFeedFolderPickerData.swift

@@ -0,0 +1,50 @@
+//
+//  AddFeedFolderPickerData.swift
+//  NetNewsWire
+//
+//  Created by Maurice Parker on 4/16/19.
+//  Copyright © 2019 Ranchero Software, LLC. All rights reserved.
+//
+
+
+import Foundation
+import Account
+import RSCore
+import RSTree
+
+struct AddFeedFolderPickerData {
+	
+	var containerNames = [String]()
+	var containers = [Container]()
+	
+	init() {
+
+		let treeControllerDelegate = FolderTreeControllerDelegate()
+		let treeController = TreeController(delegate: treeControllerDelegate)
+
+		treeController.rootNode.childNodes.forEach { node in
+			
+			guard let acctNameProvider = node.representedObject as? DisplayNameProvider else {
+				return
+			}
+			
+			let acctName = acctNameProvider.nameForDisplay
+			containerNames.append(acctName)
+			containers.append(node.representedObject as! Container)
+
+			for child in node.childNodes {
+				
+				guard let childContainer = child.representedObject as? Container else {
+					return
+				}
+				let childName = (childContainer as! DisplayNameProvider).nameForDisplay
+				containerNames.append("\(acctName) / \(childName)")
+				containers.append(childContainer)
+				
+			}
+			
+		}
+		
+	}
+
+}