Support VSCode "git clone" command

Problem to solve

Make it easy to clone your repo as an alternative to the command line. See GitHubs clone command (if there is no solid VS Code API to integrate into the git clone command an alternative could be a separate command)

Proposal

1. trigger git clone (or own GitLab git clone command)
2. select GitLab instance (support for multiple instances would be nice)
3. get a list of the repos, select one and clone it

Links / references

• GitHubs git clone
• It seems that you have to use the git extension API directly by calling registerRemoteSourceProvider(provider: RemoteSourceProvider): Disposable;, see https://github.com/microsoft/vscode/blob/e8f2b6d6ae34c7b75d4f553ccfc32928a6015909/extensions/git/src/api/git.d.ts#L244