Add internationalisation logic to lookup translation from key

[vanitabarrett]

What

Write the JavaScript logic needed for the most minimal internationalisation use case, i.e: replacing a default English string with a new string in a different language. The logic will need to be able to:

• take a translations object
• take a translation ‘key’ and look up the relevant string in the translations object

This should not cover more complex translations, e.g: pluralisation or string interpolation.

Why

So we can begin to allow hardcoded strings in our component JS to be translated
So we have a solution for translating hardcoded strings in future component JS

Who needs to work on this

Developers

Who needs to review this

Developers

Done when

• Internationalisation logic written that takes a JavaScript object of translations
• Ability to lookup a key within that translations object, and return a string
• Nicely handles instances where the key cannot be found in the translations object
• Unit tests written for the above