[AltStore] Adds basic Patreon integration

- Lists beta versions of apps when signed in to Patreon
- Lists names of Patrons with the Credits benefit

AltStore/Patreon/Patron.swift

@@ -0,0 +1,69 @@
+//
+//  Patron.swift
+//  AltStore
+//
+//  Created by Riley Testut on 8/21/19.
+//  Copyright © 2019 Riley Testut. All rights reserved.
+//
+
+import Foundation
+
+extension PatreonAPI
+{
+    struct PatronResponse: Decodable
+    {
+        struct Attributes: Decodable
+        {
+            var full_name: String
+            var patron_status: String
+        }
+        
+        struct Relationships: Decodable
+        {
+            struct Tiers: Decodable
+            {
+                struct TierID: Decodable
+                {
+                    var id: String
+                    var type: String
+                }
+                
+                var data: [TierID]
+            }
+            
+            var currently_entitled_tiers: Tiers
+        }
+        
+        var id: String
+        var attributes: Attributes
+        
+        var relationships: Relationships?
+    }
+}
+
+extension Patron
+{
+    enum Status: String, Decodable
+    {
+        case active = "active_patron"
+        case declined = "declined_patron"
+        case former = "former_patron"
+    }
+}
+
+class Patron
+{
+    var name: String
+    var identifier: String
+    
+    var status: Status
+    
+    var benefits: Set<Benefit> = []
+    
+    init(response: PatreonAPI.PatronResponse)
+    {
+        self.name = response.attributes.full_name
+        self.identifier = response.id
+        self.status = Status(rawValue: response.attributes.patron_status) ?? .former
+    }
+}