refactor(editor): extract widgets (#12304)

<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit

- **New Features**
  - Introduced two new widgets: Edgeless Dragging Area and Note Slicer, now available for use.
  - Added extension support for these widgets, enabling enhanced interaction and integration within the application.

- **Chores**
  - Updated package configurations and workspace settings to include the new widgets and their dependencies.
  - Added project references and configuration files to support modular development and build processes.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

blocksuite/affine/all/src/widgets/edgeless-dragging-area/index.ts

@@ -0,0 +1 @@
+export * from '@blocksuite/affine-widget-edgeless-dragging-area';

blocksuite/affine/all/src/widgets/edgeless-dragging-area/view.ts

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+export * from '@blocksuite/affine-widget-edgeless-dragging-area/view';

blocksuite/affine/all/src/widgets/note-slicer/index.ts

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+export * from '@blocksuite/affine-widget-note-slicer';

blocksuite/affine/all/src/widgets/note-slicer/view.ts

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+export * from '@blocksuite/affine-widget-note-slicer/view';