net-p2p/amule: Add missing build option

3.0.0 ships with ENABLE_IP2COUNTRY=OFF and upstream main shows that it
might be turned ON next releases.
Add it to CMAKE_OFF and this way we have all build options covered in port.

Also, add ChangeLog url forgotten in previous commit msg:

ChangeLog: https://github.com/amule-org/amule/releases/tag/3.0.0