feat: Added support for nested fieldsets

[tdurnford]

Description

This updates the UI Options to support nested fieldsets. If a fieldset contains another fieldset object, the <PivotFieldsets /> component renders the top level fieldsets and the <Fieldsets /> component will render the secondary fieldsets in <CollapsableField /> components.

Note, if a fieldsets contains a fieldset object as a field, then all of the fields in that fieldset must also be fieldset objects; otherwise, all of the fields must be strings representing property names. Also fieldsets deeper than two levels are not supported.

{
  fieldsets: [
    {
      title: 'set 1',
      fields: [
        { title: 'set 1a', fields: ['one', 'two'] },
        { title: 'set 1b', fields: ['*'] }
       ]
     },
     {
       title: "set 2",
       fields: ['tree', 'four', 'five]
     }
  ]
}

Task Item

Closes #4363

Screenshots

[cwhitten]

What is failing CI is unrelated to this change. I'll override to keep progress moving forward.