Allow grouping of tags

Current Situation

• Tags can be used for workflows with JOC-1637, for jobs with JOC-1810 and for orders with JOC-1693.
• Users would like to group tags based on individual criteria.

Desired Behavior

• Tags are unique objects with any number of references from workflows, orders and jobs. The grouping can include all of workflow tags, job tags and order tags.
• Users can create tag groups individually:
  • A tag group is assigned a name and a color (from RGB input).
  • A tag group holds references to any number of tags.
• Tag groups are supported by the GUI:
  • when assigning tags to objects, users can select a tag group to receive the list of available tags.
  • tags are displayed with related objects (workflows, jobs, schedules/orders) in the Configuration view and in the Workflows view.
  • tags are displayed in views from their name and from the tag group's color. The name of the tag group is made available from a tooltip when moving the mouse to a tag.
• Tag groups are supported by notifications, see JOC-1812:
  • Monitor variables are made available per tag group for workflows, jobs and orders individually.
  • A monitor variable for a tag group holds the tags that are assigned the related workflow, job or order.