gitlab-ci: migrate Windows builds away from Chocolatey
The Windows builds in GitLab CI use Chocolatey to install dependencies. Unfortunately, Chocolatey seems to be very unreliable, which causes the jobs to fail very regularly. This is a limitation that seems to be somewhat known [1]: As an organization, you want 100% reliability (or at least that potential), and you may want full trust and control as well. This is something you can get with internally hosted packages, and you are unlikely to achieve from use of the Community Package Repository. So using the Community Package Repository is kind of discouraged in case one wants reliability. We _do_ want reliability though, and we cannot easily switch to an enterprise license to fix this issue. Introduce a new script that downloads and installs dependencies directly. This has a couple of benefits: - We can drop our dependency on Chocolatey completely, thus improving reliability. - We can easily cache the installers. - We get direct control over the exact versions we install. - Installing dependencies is sped up from roundabout 3 minutes to 1 minute. [1]: https://docs.chocolatey.org/en-us/community-repository/community-packages-disclaimer/#summary Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>