survey: Initial commit of new module (closes #169)
    
    This commit makes the following changes:
    
    * Creates a new Antora module (`survey`) to better organize the
      research, work, and questions from the Fedora Project Demographic
      Survey
    * Removes "Demographic survey" page from ROOT module, removes from ROOT
      module `nav.adoc`
    * Adds `survey` module `nav.adoc` into the main Antora site
      configuration
    
    Closes #169.
    
    Signed-off-by: Justin W. Flory (he/him) <git@jwf.io>
    
    squash! survey: Initial commit of new module (closes #169)
    
    Fix table of contents
    
    Signed-off-by: Justin W. Flory (he/him) <git@jwf.io>