Add 1 as a default value for the paramater numberOfDaysOfAvailability on the backend

Background:

In order to know for how long we want the preview of the cold storage available for the user, we use in the back-end side a parameter called numberOfDaysOfAvailability.

Right now we're making this parameter a required field. But, since for now, we will establish that the default time a user can have access to a preview is 1 day. We want the API to use this value as default, so if the front-end doesn't send a numberOfDaysOfAvailability, the back-end will use 1.

Requirement:

Make numberOfDaysOfAvailability parameter optional and to have a default value of 1.

Futher info:

Probably in the future we will work on adding the possibility for the user to customize this field.