added form, context, page elements for word guessing

[zmchang3009]

• basic frontend for word guessing
• React context used to keep track of guesses in current session
• guesses are lost upon refresh, hence need to be saved into database

[zmchang3009]

• created util wordChecker on the frontend to handle guesses
  • pre-processes input (removes whitespace, to lower case, etc)
  • checks for multiple words
  • checks if word has been guessed
  • checks if word is in puzzle or if word is stopword