Restore contacts from backup

XXClient library

• Improve error handling in UdMultiLookupCallback.

xx-messenger example

• Improve backup restoration.
• Restore contacts.
• Add contact lookup feature.
• Display contact ids.
• Improve sending requests.
• Restore username from restored facts, not from restored params.

Examples/xx-messenger/Sources/AppFeature/AppEnvironment+Live.swift

@@ -37,6 +37,9 @@ extension AppEnvironment {
       db: dbManager.getDB,
       mainQueue: mainQueue,
       bgQueue: bgQueue,
+      lookup: {
+        ContactLookupEnvironment()
+      },
       sendRequest: {
         SendRequestEnvironment(
           messenger: messenger,