feat: Refactor project structure and add core library

- Migrate shared components from WPF to a new Core library.
- Introduce GroupInfo, M3UInfo, and ObservableViewModelBase classes.
- Implement M3UParser for downloading and parsing M3U files.
- Add ProgramsData for managing program lists and guides.
- Create SettingsModel for application settings management.
- Update project references in solution files.

TV Player Core/GroupInfo.cs

@@ -0,0 +1,9 @@
+namespace TV_Player
+{
+    [Serializable]
+    public class GroupInfo
+    { 
+        public string Name { get; set; }
+        public int Count { get; set; }
+    }
+}