In board context issue editing

Issue idea came from: https://gitlab.com/gitlab-org/gitlab-ce/issues/8938#note_26215928

Problem

In trello you can open up an issue in context of the board, like so:

2017-03-27_15.08.03

In GitLab this isn't yet possible (while this can be done relatively easily)

Proposal & Design

I propose the following solution:

Group

This dialog is mostly usable on screens that have enough screen real estate for it, therefore I suggest:

  • Disabling this feature on screens below 992px (it will just open the issue in a tab of its own)
  • Between 992px and 1280px it will open with the sidebar collapsed
  • Above 1280px it will open with sidebar expanded (like in the mockup)

Value

Quickly switch between issues, within the context of the issue board.

Related issues

https://gitlab.com/gitlab-org/gitlab-ce/issues/8938

CC/Call to actions

@cperessini @tauriedavis (what do you think of the closing icon in this view? and/or should the sidebar be collapsable/expandable in this view.. see "proposal" section )

@victorwu (this could be an easy win, as all content is already there)