RFC on removing support for Windows < 10

Windows 7 is EOL since 01/2020 and Windows 8.1 since 01/2023.

So I propose to remove support for Windows 8 and lower.

Since #127, we now have binary-less driver for Windows and WSL. So we can already remove the wsl-notify-send driver (wsl only) and its 3.36 MB binary that does not bring anything compared to #127.

But, if we remove support for Windows < 10, it will also allow us to:
- remove the Notifu driver (windows 7 only) and its 200kb binary
- remove the SnoreToast driver (windows>= 8) and its 1.97 MB binary

Then Windows support (either true Windows or WSL) would rely on a unique powershell-based driver, not requiring to package binaries inside JoliNotif, making it **sooooo much lighter**, and same for Castor.

Any opinions on this?