Reformat documentation to create a single searchable html file.

This is the first baby step to reorganizing the website and allowing for the documentation to be easily searchable. @jessmartin, @MichaelVacirca, please review and provide feedback. Thanks!

Commit Comments:
Reformat documentation to create a single searchable html file.
Remove unused documentation files.
Restyle documentation to improve readability.
Remove glossary and FAQ from website.
Update links to unsupported page.
Refs #2923.