Implement Trip, Activity, & Day tables, and TripService

• Created tables for Trip, Activity and Day
  • established a one-to-many relationship between Trips and Days, and a many-to-many relationship between Days and Activities
• Added missing fields to Trip, Activity and Day
• Implemented createTrip in TripService to create a new trip entry in the db
• Implemented TripDAO methods to create, update, delete and get a trip entry