Remove integration with non-git repos

[williamjallen]

This PR removes all but GitHub and GitLab from the list of repositories CDash can integrate with. This is the first in a series of PRs reducing our integration with lesser-used external tools, paving the way for better integration with git-based tools in the future. None of the code removed in this PR is tested, and it is quite likely that some of these no longer work in the first place.

[zackgalbreath]

While we're dropping support for version control systems we should also trim the list of viewers here:

https://github.com/Kitware/CDash/blob/master/app/cdash/app/Model/Repository.php#L28

[williamjallen]

While we're dropping support for version control systems we should also trim the list of viewers here:

There are a bunch of other frontend changes related to this that also need to be made. As far as I can tell, the code you linked is only used to populate the dropdown in the UI, so I left it out of this PR deliberately. As far as I can tell, the current changes should be "safe" in that they just cause CDash systems with other repositories to lose their links to those repositories. Any objections to this approach?

[zackgalbreath]

the code you linked is only used to populate the dropdown in the UI

That is my understanding as well.

the current changes should be "safe" in that they just cause CDash systems with other repositories to lose their links to those repositories. Any objections to this approach?

I'm okay splitting this effort across multiple PRs as long as we're keeping track of the corresponding frontend changes that need to be made as well.

[josephsnyder]

Things seem reasonable. I didn't find issues during brief manual testing. LGTM!