Show tags in history sidebar

[DenisaCG]

In the history panel, show the tags (if they exist) next to the commits they are pointing to.

For this, the implementation of an ITag interface was required, such that for each tag we keep not only its name, but also the id of the commit it points to.

export interface ITag {
    name: string;
    baseCommitId?: string;
}

[github-actions]

👈 Launch a Binder on branch DenisaCG/jupyterlab-git/tagsHistorySidebar

[fcollonval]

Thanks @DenisaCG