Add the Notification Banner introduced in NHS Frontend v10

[robkerrybjss]

The notification banner component from NHS.UK frontend v10 doesn't yet exist in this library.

[robkerrybjss]

I have the code written for this, I just need to be given permission to push it up!

[colinrotherham]

Thanks @robkerrybjss, I'll happily review a contribution

You can copy how we added the panel component recently if that helps?

[robkerrybjss]

Thanks, I used that as inspiration! I've put in a request to be given push access, once that's been actioned I'll spin up a PR

[colinrotherham]

For now if you make a fork instead, open a PR from there?

Appreciate it

[robkerrybjss]

Ok that's up and built ok now!

[colinrotherham]

Closed by #284 🎉