Refactor class CodecademyBadges

- get_badges: remove unnecessary variable user_information
- get_html: remove unncessary variable document
- integrate:
  - map out each_with_index, returning array of arrays
  - then hash the array
badges.rb: Make get_titles and get_dates return clean arrays

- get_titles: map over xpath results and get text out
- get_dates: map over xpath results and Date.parse the text
- integrate: no longer need to .text and .parse the titles and dates
badges.rb: use class constants for codecademy strings