CPack productbuild generator: No way to define package identifier
When creating a macOS package (.pkg) file with the productbuild generator, the package identifier (`pkgbuild`'s `--identifier` parameter) is set to:
```
"com." + CPACK_PACKAGE_VENDOR + "." + CPACK_PACKAGE_NAME + "." + component name
```
according to the [C++ source](https://gitlab.kitware.com/cmake/cmake/-/blob/d3fd518c0316b15e4680c32808788935bf8c5c3d/Source/CPack/cmCPackProductBuildGenerator.cxx#L206)
I now have to set the package id to start with "org." to reflect the organization properly (necessary for signing the package), which doesn't seem to be possible.
I'd want some variable (lile `CPACK_COMPONENT_<compName>_BUNDLE_IDENTIFIER`) or a parameter in `cpack_add_component` (from CPackComponent) where I can override this ID properly.
Thanks,
Andreas
issue