No longer publish new releases for Bower and Git submodules

[Krinkle]

We currently commit the distribution files to the tagged release commit (example). To reduce noise in the main branch, this commit is detached from it. This in turn means that native Git tooling doesn't understand version attribution well, which affects contribution and maintenance workflows. It's also one of the more manual parts of the release process.

So much for cost. What about the value proposition, and thus their original justification:

• Distribute QUnit release files through Git, permitting consumption via a Git submodule.
• Distribute QUnit release files to Bower (which internally requires us to host it in a Git tag).

Removal of this was originally proposed for QUnit 2.0 in 2016, but at the time we forgot to follow through. I'm proposing to do this for QUnit 3.0 later this year.

The recommendation for affected developers and their projects, would be to either check in a copy of the file as offered from the CDN (see release channels), or to use npm. Given the more stable and sustainable/low-tech nature of projects that tend to opt for Git sumodules, I imagine checking in qunit.js will be the smoothest option to choose. Although if projects already require use of Node.js, and have an npm-based workflow in-place, and don't support running any tests without it, then that would a viable option as well.

More details and background at #1133 (comment).