ability to configure board constraints by multiple columns

As a team using Kanban with Jira boards

I want to configure my constraints (WIP limits) by step, not only by column

So we have an accurate picture of workflow issues in our delivery

Acceptance criteria

• Minimum and maximum number contraints can be set by column (current behavior)
• Minimum and maximum number constraints can be set for a set of columns
• When constraints are defined for a set of columns the value is shown above the set of columns
• When constraints are defined for a set of columns, and the constraints are exceeded, all columns in the set are highlighted

Business case

Teams can visualize their workflow with a Kanban board. Often such boards show team workflow as a series of process steps. And to manage flow, the steps may be further divided into "doing" and "done", where the "done" column is the pool of items that have completed and not yet been pulled into the next step. For example, "Dev Doing" and "Dev Done".

WIP limits apply to both "doing" and "done", so showing one limit spanning both would provide a more accurate picture for teams of their workflow.  In the example below, "Dev" should have one WIP limit, including all items in the sub-columns of "Dev Doing" and Dev Done".