More expressive file icon

[jhuenges]

The default file icon in an upload collection only shows a white file. I would like to propose the make it more expressive by, for example, adding the file extension to the icon.

For example, a pdf file, could look like this:

I understand that this might be a breaking change, but maybe someone has an idea how this could be achieved without breaking the icon for developers who are using this icon.

Cheers!