In-app notification banners

### Your use case

#### What would you like to do?

I would like to have in-app notification banners, which would show notifications on the side/top like it would on a normal PC.

These could be offered as a replacement or addition to desktop notifications.

#### Why would you like to do it?

On all operating systems I’ve used, desktop notifications have been pretty so-so, windows’ notifications flattens them in the metro style, but also can’t stack when multiple come in, Linux’s GNOME notifications also only show one at the time, but the view time is invariable (and with element it sometimes bugs out), and MacOS is sometimes the only one to get it right.

In-app banners could maybe also seamlessly integrate with the notifications panel, with some semantic correlation.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_