Add notifications sdk v2 sample notebook to sample-notebooks

[katyrochford]

Pull Request Checklist

• [x] Changes follow the style guide
• [ ] Tests pass
• [x] Raised the PR against the develop branch
• [x] Notebook outputs do not contain any privileged data

Description of the PR

Describe the code changes for the reviewers, explain the solution you have provided and how it fixes the issue

This is a new notebook plus associated files which demonstrates how to setup an email notification with an html body which includes more information than you initially receive from the event body

[review-notebook-app[bot]]

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[hanialsibai]

/LGTM