Allow entering a description per queue to show above the queue list

Problem/Motivation

Site managers that manage the entity queues often have problems to understand how to manage these lists, which internal rules to consider, which entity types appear in the autocomplete, etc.

Like node types have the option to enter a description that appears on the node create / edit form, it would be great (and simple) to allow entering a description per entity queue that should appear above the sortable list.

Steps to reproduce

Manage entity queue entries as regular user and need helpful information

Proposed resolution

See above