CEX-570 add blur prop to input component

[hxtomprice]

What does this PR do? (please provide any background)

Adds an handleBlur prop to the Input component. This will allow us to run functions when a user has finished interacting with an input field. Currently there is only a handleChange prop which will run whenever a user types.

What tests does this PR have?

test/components/input-test.jsx

How can this be tested?

I've created the toolkit-blur-test branch in the react-car-reg-lookup for testing this. npm-link the toolkit, run an npm run build and you will be able to test these changes in that repo.

When you blur on the input field you will see a console.log with the value of the input field

Screenshots / Screencast

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