"issues/comments" dialog on glossary items

[kohlhase]

We should have a "comments/issues" dialog on the glossary entries in http://mathhub.info/mh/glossary (probably only when they are expanded to the definition or so). It think we should use the GitLab issues functionality at http://gl.mathhub.info for comments/issues, since it exists, is well-tested, and has a web service interface. The good thing is that we know

• what archive/file the glossary entry comes from, so we can put it to the right archive on http://gl.mathhub.info and generate a lot of information into the issue that makes the issue easier to track.
• the author of the binding, and the author of the signature, so we can notify them.
  The "comments/issues" dialog may also show the interested user the existing issues on this terminology module, so that duplicate issues are avoided.