Update 'What is ACSU?'

[ef23]

• content of this page could be updated, can work with eboard/team leads on updating content
• our purpose could be updated, also work with eboard/leads
• pictures would be nice
• combine "Mentorship" into this tab
  • "similarly, we could combine this with with "What is ACSU?" so that we have fewer tabs to confuse people, especially since the per-event/program tabs have very little purpose, since we do some much on facebook now."
  • "Need advice about classes, landing your first internship, or doing research on campus? Want to meet other awesome students interested in computer science? ACSU's mentorship program is just for you!"
  • people may be confused on how to actually join, should make it clear we need to join through facebook event
  • guidelines & expectations content may not have been updated too recently
• could be /about.html