Add delivery_date column in the backend Azure SQL Database

[SophiaKaterinis]

New feature that allows the addition of a new field in the delivery tracking software.
Addition of a delivery_date column in the backend Azure SQL Database

[SophiaKaterinis]

Feature was added but then reverted.

If feature is requested again, follow these instructions:

1. In app.py modify the following:
   1.a. Order class to include delivery_date = Column('Delivery Date', DateTime)
   1.b. @app.route add_order function to include delivery_date = request.form['delivery_date']
   1.c. new_order object to include delivery_date=delivery_date
2. In order.html modify the following:
   2.a. <th> elements to include <th>Delivery Date</th>
   2.b. <td> elements to include <td>{{ order.delivery_date }}</td>
   2.c. <form> element to include <label for="delivery_date">Delivery Date:</label>
   and <input type="date" id="delivery_date" name="delivery_date"><br><br>