Move DAVE manual test suite out of the Tails release process

In #11799 (closed) we’ve added DAVE tests to https://tails.boum.org/contribute/release_process/test/. That’s a great start! But, there’s a but:

• Most of these tests are orthogonal to the Tails release process, so it’s suboptimal to have on the critical path to a Tails release. The fact that some of these tests seem too unclear, at least for a few of us, doesn’t help (#12005 (closed)).
• The goal of #11799 (closed) was “to detect problems with new Firefox versions early enough”, but the testing instructions merely require “a Firefox-based browser”; so if the tests are performed in the ISO under testing, i.e. with an oldish Firefox ESR, then this testing process is not addressing the initial goal; and if the tests are performed elsewhere, with a recent Firefox, then we’re not verifying that DAVE works well in the upcoming version of Tails, although that would be a useful additional goal of running these tests during the Tails release process.

So I propose:

1. Keep the simplest test in the Tails manual test suite: download, pause/resume, appears in the downloads list.
2. Move all other tests to a dedicated DAVE test suite, that shall be run (probably by the DAVE maintainer, but suggestions are welcome):
   1. at DAVE release time;
   2. whenever a new Firefox is released.
3. Consider automating these tests before we get bored and sloppy and start secretly skipping the “whenever a new Firefox is released” tests ;)

But I might have missed some reasons why things currently are done like this, so please correct my assumptions/reasoning if needed :)

Parent Task: #12328 (closed)

Related issues

• Related to #12005 (closed)
• Related to #15188 (closed)

Original created by @intrigeri on 12683 (Redmine)