Wizard: allow adding custom products

[giordano]

Currently the wizard automatically detects only executable binaries and shared libraries as products in standard directories, anything else is ignored. In particular, there is no way to specify a FileProduct, or the already supported products but in non-standard directories. If a build happens to only have non-ExecutableProduct/LibraryProducts, or only in non-standard directories, the build fails, leaving the user helpless.

[Moelf]

running into this as the "executable" produced is only a python script:

• add madgraph Yggdrasil#6236