Create app/branch deployment

[GCHQ-Developer-530]

Summary

In our other repos (ic-ui-kit and ic-design-system) we deploy using github pages, we should do the same thing in this repo.

💬 Description

We should deploy main, develop and branches to make it easier to see any updates made to the app.
Branch deployments should be linked in pull requests like we do in our other repos (here is a workflow file as an example of how to do that)

💰 Use value

Everyone can view the app without having to run it locally.