Refactor data providers and update abstractions

- Removed obsolete data providers: `AnchorCollectionDataProvider`, `ContentsDataProvider`, and others, consolidating logic into new composable providers.
- Added `ComposeDataProviders`, `SelectDataProvider`, and `RelationalDataProvider` for improved flexibility and reusability.
- Introduced `IManySelectionComposableDataProvider` interface to support multiple-node selection.
- Enhanced `UnitDownloader` with more robust progress tracking.
- Updated package references and project dependencies for consistency.
- Improved error handling in `StealthConfig` initialization for better fallback on browser drivers.
- Incremented project version to 2.4.5.

Beam.Abstractions/IManySelectionComposableDataProvider.cs

@@ -0,0 +1,9 @@
+using HtmlAgilityPack;
+
+namespace Beam.Abstractions;
+
+public interface IManySelectionComposableDataProvider<out T> : IDataProvider<T> {
+    public T ManyGet(HtmlNode[] node);
+    public HtmlNode[]? SelectMany(HtmlDocument doc);
+    public HtmlNode[]? SelectMany(HtmlNode[] node);
+}