[AT]: Use new() Instead of create() for Constructor Functions

[itsyaasir]

Feature description

As per IOTA conventions, It is recommend to use new for creating object as a constructor functions.

Motivation

N/A

Requirements

N/A

Open questions

No response

Are you planning to do it yourself in a pull request?

Yes

[chrisgitiota]

In the existing Notarization code we used:

• new() functions to return the created object instance
• create() functions (calling new() internally) to send the created object to the sender after creation

We could stick with this pattern also for AT.