Make it possible to change form data after first render

__Is your feature request related to a problem? Please describe__

On Zeebe Tasklist if we try to complete a Task that was already completed we receive the updated Task and update the values on the form. To do that we need a way to update the values after the first render.

__Describe the solution you'd like__

```js
const form = createForm({
// ...
});

form.setData(newData);

// or

form.setProperty('data', newData)
```

__Additional context__

Currently I'm using `form.setState({ data })` for that, but I assume that it's not public API and not very wise to use it on long term

Start at the public createForm API and inspect how the existing form.setState({ data }) path updates rendered values. Done means a supported public way to replace form data after the first render, with the updated values visible on the form.

Written by the indexing model from the issue text.