Implemented taskId aws function

[nataliagourova]

The code in this commit is deployed as a lambda function via a zip file that contains pymysql dependencies. The GET method functionality may be tested at https://mchfd7t6l4.execute-api.us-west-2.amazonaws.com/users/1/tasks/1. Other methods may be tested in Postman.

notes on testing:

• logging level is currently set for "debug" and detailed logs are available on CloudWatch here
• "completed" field value needs to be passed as string, either "0" or "1"
• "date" field value needs to be passed in the "11/11/12 11:11:11" format
• PATCH takes any number of parameters, for example:

  {
  "dueDate": "11/11/12 11:11:11",
  "completed": "0"
  }

• PUT takes 5 required parameters, dates may not be null, for example:

  {
  "title": "vitae",
  "description": "sem, vitae aliquam eros turpis",
  "dueDate": "11/11/12 11:11:11",
  "completed": "1",
  "completedDate": "11/11/12 11:11:11"
  }