Add basic correctness testing of Linux packages to nightly tests

[jabraham17]

Adds basic correctness testing of Linux packages to nightly tests. This improves upon the unused util/packaging/common/test_package.py script and actually begins using in the nightly build script. This should validate the packages and catch mistakes when making changes to the package configs

Tested that __test_package works with existing packages.

[Reviewed by @jhh67]