[#16] Added CrawlSession model to keep track of latest activities & sessions

Full Commit Changes:
 - Changed name of namespace to Acme\Schedule instead of Acme\ScheduleCrawler
 - Added ScheduleRetriever service
 - Added CrawlSession model, migration, repositories
 - Modified Storage of Activities Sessions to keep track of crawl session too.
 - Added dependency on Carbon
 - Added route to get activity sessions for this week

To Do:
 - Need to modify crawler to do parsing for special title conventions e.g. Badminton/Table Tennis
[#14] Modified scraper to parse through activity title to separate multiple activities and women-only activities.