Add admin request type

Sources/PushAPI/AdminRequest.swift

@@ -0,0 +1,13 @@
+import Foundation
+
+/**
+ Authentication used to request application changes by an administrator
+ */
+public struct AdminRequest: Codable {
+
+    /// The SHA-256 hash of the admin key
+    public let keyHash: Data
+
+    /// The application id with which the request is associated
+    public let application: ApplicationId
+}