Introduce enum for scope of search bar

This simplifies the handling of the indices in the search bar scope list, replaces strings as keys and allows a proper localization not breaking any logic.

pass/Helpers/SearchBarScope.swift

@@ -0,0 +1,21 @@
+//
+//  SearchBarScope.swift
+//  pass
+//
+//  Created by Danny Moesch on 05.03.19.
+//  Copyright © 2019 Bob Sun. All rights reserved.
+//
+
+enum SearchBarScope: Int, CaseIterable {
+    case current
+    case all
+
+    var localizedName: String {
+        switch self {
+        case .current:
+            return "Current".localize()
+        case .all:
+            return "All".localize()
+        }
+    }
+}