Add Team population query

Added the functionality for each find operation run on Team to return
with populated references for User, League and Players
Including the list of teams in the league view
Change view partial for creating team to a modal view partial
Created an angular controller for the create team modal

- Included a createTeam method in the league controller which triggers
the create team modal
- Created newTeamModalController which controls the modal window for
creating a new team
- Refactored TeamsController to remove the create method as that's
already being handled in the modal controller