Implement feature flags and update views

This commit implements feature flags using the "ylsideas/feature-flags" library and updates various frontend views to show or hide sections based on the feature flag. Additionally, a new migration file is created for the features database table and the LibraryItem model is updated with a new searchLibraryItems function. The composer.json and composer.lock files are updated to include the new dependencies.

resources/views/livewire/news/intern-article-view.blade.php

@@ -340,6 +340,7 @@
         });
     }})"></div>
 
+    @feature('nostr.groups')
     @push('modals')
         <div wire:ignore class="z-50 hidden md:block">
             <script src="https://cdn.jsdelivr.net/npm/party-js@latest/bundle/party.min.js"></script>
@@ -353,4 +354,6 @@
             <link rel="stylesheet" href="{{ asset('dist/einundzwanzig.chat.css') }}">
         </div>
     @endpush
+    @endfeature
+
 </div>