Add localized search functionality for contacts (#244)

- Introduced new localization keys for searching contacts, users, favorites, repeaters, and room servers in multiple languages.
- Updated localization files for Italian, Bulgarian, German, English, Spanish, French, Dutch, Polish, Portuguese, Russian, Slovak, Slovenian, Swedish, Ukrainian, and Chinese.
- Enhanced the contacts screen to dynamically display search hints based on the selected contact type filter.
- Modified the map screen to utilize the new search functionality for contacts without a number.

lib/l10n/app_localizations_de.dart

@@ -677,7 +677,35 @@ class AppLocalizationsDe extends AppLocalizations {
       'Kontakte werden angezeigt, wenn Geräte eine Ankündigung machen.';
 
   @override
-  String get contacts_searchContacts => 'Suche Kontakte...';
+  String get contacts_unread => 'Ungelesen';
+
+  @override
+  String get contacts_searchContactsNoNumber => 'Kontakte suchen...';
+
+  @override
+  String contacts_searchContacts(int number, String str) {
+    return 'Suche Kontakte...';
+  }
+
+  @override
+  String contacts_searchFavorites(int number, String str) {
+    return 'Suche $number$str Favoriten...';
+  }
+
+  @override
+  String contacts_searchUsers(int number, String str) {
+    return 'Suche $number$str Benutzer...';
+  }
+
+  @override
+  String contacts_searchRepeaters(int number, String str) {
+    return 'Suche $number$str Repeater...';
+  }
+
+  @override
+  String contacts_searchRoomServers(int number, String str) {
+    return 'Suche $number$str Raumserver...';
+  }
 
   @override
   String get contacts_noUnreadContacts => 'Keine ungesehene Kontakte';