Endpoint to return number edits svg badge

linked to #14 (Meta table)

Each time a new version (edit) of the issue description or a comment of the issue is saved, the meta table will display the new incremented number of edits. We can update directly the issue description of the new number via the Github API, however a nicer solution is to use a svg served by the "github-backup" server.
So in a similar way to https://github.com/dwyl/hits-elixir we need to:
- [x] create an endpoint ex: ```/edit-count/{issue_id}``` which will return an svg image
- [x] insert the svg image similar to ```[](https://github.com/dwyl/hits-elixir)``` [](https://github.com/dwyl/hits-elixir)

format of the hit-elixir svg:
```

```