Replies to cover letter should be shown on series page

[ruscur]

If there are replies to the cover letter of a patch series, they should show up in a comments section of the series page just as they do on patches.

[belenbarrospena]

The redesign of the series page does not have a comments section for series, but they could show below the cover letter itself. Like so

http://belenbarrospena.github.io/patchwork-redesign/series-r4.html#comment1

Let me know if that would work. By the way, if you people have any feedback on the new series details page

http://belenbarrospena.github.io/patchwork-redesign/series-r4.html

Or the patch page

http://belenbarrospena.github.io/patchwork-redesign/patch1.html

Do let me know. They are not implemented yet, so we have time for improvements.