Removed throws Exception from the TaskService methods

AFDP-158
Created REST controller for task retrieval with its unit test

AFDP-159
Created Task model and collection

AFDP-160
Created TaskService and added Backbone.Service library

AFDP-160
Updated modal view to display the available tasks

AFDP-160
Removed throws Exception from PropertyTaskRepository.init method

AFDP-158