MESSENGER-3425 permalink prefix developer settings screen

Config/BWIBuildSettings.swift

@@ -567,6 +567,10 @@ class BWIBuildSettings: NSObject {
     // MARK: User Search
     var sortUserSearchResultsAlphabetically = true
     
+    // MARK: Permalinks
+    var permalinkPrefixSettings = false
+    var permalinkPrefixes: [String] = []
+
     // MARK: Client error search term
     var clientErrorSearchTerm = "Request failed: client error"
 }