Publish on OpenVSX

This extension is currently available on VisualStudio Marketplace, which can only be legally used by the Microsoft build of VSCode. Since this is a non-free build, I am using [VSCodium](https://vscodium.com/), which is using [OpenVSX](https://open-vsx.org/) as its marketplace.

This extension was [published on OpenVSX](https://open-vsx.org/extension/firefox-devtools/vscode-firefox-debug), but it is unofficial, and it is not up-to-date. The best option would be to follow the [documentation to create a namespace](https://github.com/eclipse/openvsx/wiki/Namespace-Access) and upload the extension there. Of course, this requires some work. There is an [easiest path](https://github.com/open-vsx/publish-extensions), but it should be used by extension users as a wish list.

L’issue ne nomme aucun fichier du dépôt, test ou point d’entrée de publication. Commencez par la documentation OpenVSX Namespace Access liée et examinez comment cette extension est actuellement publiée sur Visual Studio Marketplace ; la tâche est terminée lorsque le projet contrôle un namespace OpenVSX et y publie une extension officielle à jour.

Rédigé par le modèle d'indexation à partir du texte de l'issue.