Ability to add call-out boxes to all issue types

Related to help text and tool tips for fields, we would like the capability to be able to add info or call-out boxes to layouts. Fields that are purely to provide info or warnings, in the same way that you can use the call-outs in the notes functionality.

This will be especially useful when asking our PMs to input complex information, especially using custom tables and worksheets.

I've added a mock-up of what I think it could look like.