Adding gitqlient

[francescmaestre]

Describe your changes

Adding GitQlient plugin to the extension registry.

Checklist

• I have run npm run all to validate my changes
• I have made sure my commits are signed
• I have added an entry for new Extensions in CODEOWNERS
• I have read and I agree with the Qt Creator Extensions Store Publisher Terms

[CLAassistant]

All committers have signed the CLA.

[Maddimax]

Thank you very much for your contribution! We are still not quite done with all the legalese, but as soon as that is done we will merge your request.

[lavonardo]

Thank you for your submission and apologies to have kept you waiting.
With the incoming release of Qt Creator 18, we will be merging the pull request, and thus GitQlient will be available in the extension directory.
However, as your extension is written in C++ and thus dependent on the version of Qt Creator, could you please update the pull request to refer to versions that have been built against Qt Creator 18.

[francescmaestre]

I'll try to do it during the week, thanks!

[francescmaestre]

@lavonardo @Maddimax After some wrestling with the SSH keys I finally manage to sign commits again.

I've updated the new SHAs for the plugin and the names/IDs inside. Thanks for the review!