Package distribution files the way they should be uploaded to S3

We produce 6 archives per build:  Linux, MacOS, and Windows archives for OpenShift / Kubernetes containing YAML files, command-line utilities, etc.

These files are all .tar.gz out of the build, but for upload to S3 the Windows and MacOS files should be .zip.

Also, the filename punctuation is slightly wrong: there should be a - between the build number and platform name, rather than a _.