Develop role presentation examples page that illustrates the effects of the presentation role on the accessibility tree

[mcking65]

Draft a page of examples and illustrative text that explain and reinforce the guidance provided in the section Intentionally Hiding Semantics with the presentation role that was drafted for issue #79.

Work has been started in the "issue182-presentation-examples" feature branch:

• Initial rough draft in the "issue182-presentation-examples" feature branch.
• Draft of linking paragraph from the role presentation section in the "issue182-presentation-examples feature branch.