Add package installation testing

[wagoodman]

This adds the ability to test the deb/rpm packages as well as do a smoke-ish like test for running on mac, windows, and linux. Any comments on approach/improvements are welcome!

[eine]

I am not sure about "This will run on merge to master, and for PRs with folks that also are part of the GHA beta". On the one hand, the condition is changed in this PR to on: [ push ]. On the other hand, even if contributors are not part of the GHA beta, when a PR is opened, tests should be executed. Moreover, if the contributor is part of the beta, tests will be executed twice: one as a push on the fork, and another time as a PR here.

[wagoodman]

@1138-4eb quite right, when I tried this out it was in a private repo, which I believe why it was not running --comment removed.

[eine]

@wagoodman, IMHO you should keep pull_request and use if fields to avoid specific steps being executed, should you want to. Otherwise, you will need to blindly review PRs, or go to the forks to see the tests.

[wagoodman]

Ah I hadn't realized this is what you were pointing out. I'll go back and add this in, thanks!