Style and format issue board cards

Resources

PM @victorwu | UX @cperessini

Part of

#25698 (closed) Issue board as a workflow tool

New styling and formatting for issue board cards.

Applies to both the regular view of issue boards, and the add issue modal: https://gitlab.com/gitlab-org/gitlab-ce/issues/26205

Include relevant information.

Design

• Issue number moves next to the issue title
• Assignee picture moves to the top-right corner
• Issue title and number wrap to to the next line before overlapping with the assignee picture
• Labels are left-aligned to the card

Card design

Measurements and attributes

Issue title	Assignee picture	Labels