Improve club fairs page to be more detailed and accurate

[jwflory]

This commit specifically addresses the following:

• Follow style guide for Sphinx-based docs
• Add section specifically on club fair for incoming students
• Change requirements on staffing
  • Two eboard members required
  • Suggestions for ways to prep for staffing booth
• Rework preparation and setup section:
  • Registering / preparing for fair
  • Add packing list
  • Detail day-of setup
• Add note about retrospectives in post-fair follow-up

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Tagging RITlug/tasks#8 for tracking purposes.