[FEAT] - Custom icon on all modules

[scoopandrun]

First, thank you for this excellent and simple library.

Is your feature request related to a problem? Please describe.

No. Preset icons do not cause any issue but sometimes do not fully represent the meaning of the message to the user.

Describe the solution you'd like

Just like the Notify module allows us to use a custom Font Awesome icon, the possibility to customize the icon for all modules would be very nice.
Also, maybe add the possibility to use other icon sets (like Material Icons, Bootstrap Icons, etc.)?

Describe alternatives you've considered

At the moment, use of the default icon seems to be the only simple solution, although it seems possible to change the icon with JavaScript.