Add loader button

Need to research to see what the requirements are, but the idea would be that we could have `` that would disable the button and add some sort of loading indication visually and to assistive technology users.

```jsx

```

There's a few things that need answers:

* How will this work with various screen readers?
* What's the impact of different solutions?

This kind of component would be extremely useful in the extension, as there are several interactions that could make use of this.

## Inert State

```jsx
Submit
```

## Loading State

How to announce status changes? With `aria-disabled` we would also need to squash any `key`/`click` events.

```jsx

Submit

```