Comment issues without leaving boards view

Description

(Include problem, use cases, benefits, and/or goals)

On issues boards section, If I need to apply a command or just comment, I has to enter to the issue detail, loosing boards view 😢

Proposal

So, If I click on the issue, will appear the summary at the right of screen. That would be nice if you put something like a textarea, to do "fast" comments or apply "fast" commands

Thanks, great job, loving gitlab <3