[Lazarus] Wish about Lazarus readme

[Mattias Gaertner]

> AlexeyT via Lazarus <lazarus at lists.lazarus-ide.org> hat am 10. Dezember 2017 um 16:12 geschrieben:
> 
> > , because ...?
> 
> because then users can find authors of Palette icons, menu icons,
> dialogs icons, and tell them feedback.

Installed packages add icons too.
All packages contain an author field. And the authors are often mentioned in the readme of the folder as well. For consistency the icon contributors should be added in the images/README.txt.

Mattias