Adds VS App Center analytics + crash reporting

Currently tracks install, refresh, and update app events.

AltStore/Extensions/FileManager+DirectorySize.swift

@@ -0,0 +1,36 @@
+//
+//  FileManager+DirectorySize.swift
+//  AltStore
+//
+//  Created by Riley Testut on 3/31/20.
+//  Copyright © 2020 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+extension FileManager
+{
+    func directorySize(at directoryURL: URL) -> Int?
+    {
+        guard let enumerator = FileManager.default.enumerator(at: directoryURL, includingPropertiesForKeys: [.fileSizeKey]) else { return nil }
+        
+        var total: Int = 0
+        
+        for case let fileURL as URL in enumerator
+        {
+            do
+            {
+                let resourceValues = try fileURL.resourceValues(forKeys: [.fileSizeKey])
+                guard let fileSize = resourceValues.fileSize else { continue }
+                
+                total += fileSize
+            }
+            catch
+            {
+                print("Failed to read file size for item: \(fileURL).", error)
+            }
+        }
+        
+        return total
+    }
+}

AltStore/Extensions/UIColor+Hex.swift

@@ -10,6 +10,17 @@ import UIKit
 
 extension UIColor
 {
+    // Borrowed from https://stackoverflow.com/a/26341062
+    var hexString: String {
+        let components = self.cgColor.components
+        let r: CGFloat = components?[0] ?? 0.0
+        let g: CGFloat = components?[1] ?? 0.0
+        let b: CGFloat = components?[2] ?? 0.0
+
+        let hexString = String.init(format: "%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)), lroundf(Float(b * 255)))
+        return hexString
+    }
+    
     // Borrowed from https://stackoverflow.com/a/33397427
     convenience init?(hexString: String)
     {