Use an alternative to ref for the GitLab backend

[wjharney]

Is your feature request related to a problem? Please describe.
The ClearURLs browser extension strips the ref query parameter from URLs. The GitLab backend relies on the ref query parameter to function properly, and posts cannot be changed without it.

Describe the solution you'd like
The APIs for the GitLab backend should use an alternative query parameter (perhaps reference), to avoid being removed by ClearURLs or other tracker blockers.

Describe alternatives you've considered
I have also filed bugs with ClearURLs and GitLab to address the issue.

Additional context

• ClearURLs has 80k users in Chrome, and 66k in Firefox. It is also officially recommended by Mozilla.
• Stripping ref is a fairly basic tracker protection. I don't know of any extensions other than ClearURLs that do it, but I suspect that it is not the only one.

[erezrokah]

Hi @wjharney, this doesn't seem like an issue with Netlify CMS and impacts other sites as well (not just GitLab). See ClearURLs/Addon#93.

My expectation is that ClearURLs should be smart enough not to remove all ref parameters, but only those that are used for tracking, or at least provide a way to opt out from certain rules for specific hosts.

Even if we find a solution to ref this might come up for other existing parameters, or even new ones when we add new features.

Closing the issue. Please comment if you have more questions/feedback.