Add Ability to Add First and Last Name fields via the az ad user create Command

== Feature Description==
Customer would like to add the First and Last Name as Optional Parameters to set programmatically when executing the az ad user create command

== Context ==
Currently, the az ad user create command has some required and optional parameters. The closest parameter to a First Name and Last Name is Display Name, however in the Azure Portal, First Name and Last Name are entries that can be set if a user is created within the Portal GUI.

Customer wants to programmatically have these options available during user creation

== Business Justification ==
Customer creates many new users programmatically via Az CLI. The inability to add the First and Last Name programmatically requires additional steps to set these parameters which is time consuming

== Use Case ==
1. Customer leverages document: az ad user command
2. Customer executes programmatic creation of a new user
3. Customer sets the Display Name but unable to set the User's First and Last Name
4. Customer has to set the First and Last Name via Portal GUI method as it is not available as a parameter option

== Workaround ==
Customer would have to create a new user programmatically and go into the Azure Portal to update the user entry. This is not desired as it is time consuming as new users are frequently created in their Azure AD Tenant

3. Customer executes programmatic creation of a new user3. Customer sets the Display Name but unable to set the User's First and Last Name4. Customer has to set the First and Last Name via Portal GUI method as it is not available as a parameter option
Workaround | Customer would have to create a new user programmatically and go into the Azure Portal to update the user entry.  This is not desired as it is time consuming as new users are frequently created in their Azure AD Tenant

Feature Description Customer would like to add the First and Last Name as Optional Parameters to set programmatically when executing the az ad user create command
Context Currently the az ad user create command has some required and optional parameters. The closest parameter to a First Name and Last Name is Display Name, however in the Azure Portal, First Name and Last Name are entries that can be set if a user is created within the Portal GUI. 

Customer wants to programmatically have these options available during user creation
Business Justification Customer creates many new users programmatically via Az CLI. The inability to add the First and Last Name programmatically requires additional steps to set these parameters which is time consuming
UseCase
1. Customer leverages document: [az ad user | Microsoft Docs](https://docs.microsoft.com/en-US/cli/azure/ad/user?view=azure-cli-latest#az_ad_user_create)

2. Customer executes programmatic creation of a new user

6. Customer sets the Display Name but unable to set the User's First and Last Name

7. Customer has to set the First and Last Name via Portal GUI method as it is not available as a parameter option

Workaround
Customer would have to create a new user programmatically and go into the Azure Portal to update the user entry. 

This is not desired as it is time consuming as new users are frequently created in their Azure AD Tenant