Re restore

Based on #10. Can now restore a piece of content. The revision fields and last modified timestamps are updated automatically.

A caveat is that you may find yourself having to modify the required fields in Composer to be able to publish the content again.

The API URL is still hardcoded. Let's have a chat about how to solve that in a way we're happy with.
Can you split this out into a another file to make it more manageable? Realise it's just a simple app but those are famous last words and we might end up with something enormous before we know it!