feat: add dnd components

[brionmario]

Purpose

This pull request introduces a new Drag and Drop (DnD) feature for the React component library. The main changes include adding new components for DnD functionality, updating the storybook configuration to include the new DnD component, and adding corresponding styles and documentation.

New DnD Feature:

• packages/react/src/components/dnd/DnDProvider.tsx: Added DnDProvider component to provide drag-and-drop context to its children.
• packages/react/src/components/dnd/DnDContext.tsx: Added DnDContext to manage the drag-and-drop context.
• packages/react/src/components/dnd/DraggableNode.tsx: Added DraggableNode component to make any node draggable within a drag-and-drop context.
• packages/react/src/components/dnd/DroppableContainer.tsx: Added DroppableContainer component to handle the re-ordering of nodes within a drag-and-drop context.

Storybook and Documentation Updates:

• packages/react/.storybook/story-config.ts: Updated storybook configuration to include the new DnD component. [1] [2]
• packages/react/src/components/dnd/DnD.stories.mdx: Added stories and documentation for the new DnD components, including examples and usage instructions.

Styling:

• packages/react/src/components/dnd/draggable-node.scss: Added styles for the DraggableNode component.
• packages/react/src/components/dnd/droppable-container.scss: Added styles for the DroppableContainer component.

Drag & Drop Story

Related Issues

• Fixes: Need a set of hooks and components to easily implement a Drag & Drop (DnD) usecase. #311

Related PRs

• N/A

Checklist

• Figma Board Updated. (Mandatory for Icon and Component PRs. If you don't have access, please ask the core team to update it.)
• UX/UI review done on the final implementation.
• Story provided. (Add screenshots)
• Manual test round performed and verified.
• Unit tests provided. (Add links if there are any)
• Documentation provided. (Add links if there are any)

Security checks

• Followed secure coding standards in http://wso2.com/technical-reports/wso2-secure-engineering-guidelines?
• Ran ESLint & Prettier plugins and verified?
• Confirmed that this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets?