Add aMule 3.x as an optional application

Hi Ultra.cc team,

I would like to suggest adding support for aMule 3.x as an optional application.

The aMule project has recently been revived after many years of inactivity, and the new 3.x releases bring significant improvements in performance, stability and maintenance compared to the old 2.3.3 version. The project is actively maintained again and is available as an AppImage, making deployment relatively straightforward.

I know that eD2k/Kad is a niche use case nowadays, but there are still users who rely on it, and having an up-to-date version available on Ultra.cc would be a great addition.

I recently managed to get aMule 3.0.1 (amuled + amuleweb) running successfully on a headless Linux system, so if you decide to evaluate adding it, I'd be happy to help with testing or provide feedback.

Thanks for considering the suggestion, and thanks for the great service!