Edit board config without modal

Continuation of https://gitlab.com/gitlab-org/gitlab-ee/issues/7929.

In this issue, we actually remove the existing modal, and replace with an inline editing mechanism.

As part of this issue, we should also make sure that we can filter/configure properly for labels, assignees, and weights, in particular:

• Labels
  • Any or None: 0 or more labels, which is having no labels filter
  • None: 0 labels
  • Any: 1 or more labels
  • One or more specific labels
• Assignees
  • Any or None: 0 or more assignees, which is having no assignees filter
  • None: 0 assignees
  • Any: 1 or more assignees
  • One or more specific assignees
• Weight
  • None: No weight assigned
  • Any: Weight is 0, 1 , 2, etc.
  • Any or None, which is having no weight filter
  • Specific weight value

You can change the board title in this mode.

Initial design concepts