[ADD] Search bar for BrowseView on iOS 15

AltStore/Protocols/Filterable.swift

@@ -0,0 +1,23 @@
+//
+//  Filterable.swift
+//  SideStore
+//
+//  Created by Fabian Thies on 01.12.22.
+//  Copyright © 2022 SideStore. All rights reserved.
+//
+
+import Foundation
+
+protocol Filterable {
+    func matches(_ searchText: String) -> Bool
+}
+
+extension Collection where Element: Filterable {
+    func matches(_ searchText: String) -> Bool {
+        self.contains(where: { $0.matches(searchText) })
+    }
+    
+    func items(matching searchText: String) -> [Element] {
+        self.filter { $0.matches(searchText) }
+    }
+}