feat/#137: useImperativeHandle to expose validation method, notification messages

This MR includes:

• Make use of useImperativeHandle for exposing the validation function using ref
• Add validation function to the return value of useRoger
• Improve validations logic to handle different format of data
• Add Notifications component and state hook to display error messages when form fields are collapsed

To test locally:

• Checkout the branch and navigate to Roger.stories.tsx comp.
• Modify HA story by removing data sent to Roger and toggle of hideActionButtons: false, for displaying action buttons for testing purpose.

Closes: #137