BREAKING Use component wrapper on big number component

[AshGDS]

What

• Adds the component wrapper to the big number component
• This is a breaking change, as it renames data_attributes to nested_data_attributes, as those data attributes were being used on a child component - data_attributes is now for data attributes applied to the parent HTML element. I went with the name nested_data_attributes as it can either be on a span or a tag depending on what is passed to the component.
• This should only affect two templates which I verified using this search criteria.
• Also fixes some incorrect documentation, and removes the shared helper as the component wrapper now handles margin_bottom values.

Why

As the trello card states:

Standardising our components to use the component wrapper helper will reduce code, increase standardisation, and improve future feature implementation speed.

Visual changes

Examples have some description changes.