Virtual Laser Pointer

# Description

At the moment many virtual conferences are happening. It would be great to have a virtual laser pointer. This laser point should follow the mouse. This would help to point on specific things on slides. A user should be able to control the pointer by either move the mouse over the real slides or by move the mouse over the preview in the presenter view.

### Proposal

There could be a Pointer component, which could be added to a template. This Pointer component should have a default color and form - maybe a red circle. It should also be possible to change the form and color via props. It should also be possible to deactivate/hide the pointer by pressing e.g.: Alt/Option + L.

Proposed Props:

```
{
'shape': PropTypes.oneOf(["rect", "circ", "img"]),
'color': PropTypes.string # only applicable, when shape !== "img",
'src': PropTypes.string # only applicable, when shape == "img",
'size': PropTypes.number
}
```