[DOCS] Create documentation around how WCAG guidelines affect user choices in Theme Builder

## Problem/Concern

Related to #750.

The goal of this issue is to identify and link relevant WCAG guidelines in 2.1 and 2.2 to the appropriate atoms and molecules in Theme Builder. This issue should also result in the text/documentation that can be displayed to the user in a contextual way (#753).

Start by reviewing related issues #750 and #753, then inspect the Theme Builder's atoms and molecules to identify where WCAG 2.1 and 2.2 guidance belongs. Done means relevant guidelines are linked to the appropriate components and contextual user-facing documentation is defined.

Written by the indexing model from the issue text.