Frontend setup

There is a route existing for setting up the project :
create the first user etc etc
```
POST {{hostname}}/setup
Content-Type: application/json

{
"username": "decima",
"password": "password"
}
```

this route should also setup a jwt key in a config file but one issue at a time!

There is no front on this route, but we should have, so let's add some and ensure the user cannot use the app without calling an initial setup.

Start by tracing the existing POST /setup route and the current application entry point. Determine where the initial setup UI belongs and how access is currently handled; done means the setup form can create the first user and the rest of the app cannot be used before setup is completed.

Written by the indexing model from the issue text.