[FEATURE] Add macro to have licenses ready at runtime

**Is your feature request related to a problem? Please describe.**
I would like to be able to display all the licenses in my program at runtime.

**Describe the solution you'd like**
I'd love to have a macro which would return a Vec or Map with the libraries and their licenses.
That way I could just add a subcommand or settings page (depending on if it's a Gui or CLI program) where I display all the attributions correctly.

**Describe alternatives you've considered**
Save the licenses in JSON, embed that json and parse it when needed.

**Additional context**
I don't think there is any. I'd just love a macro which returns A vec akin to the JSON function