Fix powerview addnetuser

[asantoma]

Describe your changes

I've added the missing Add-NetUser function to the powerview PowerShell script, it seems to have gotten removed in 12138db. I've also updated the add_netuser.yaml file by removing the documentation stating an Empire stager is executed at logon for the newly created user (the Add-NetUser function doesn't do this). I've removed the Listener parameter because it caused the function to crash since it's not in its parameter list and modified needs_admin to be true since the function requires administrative privileges to successfully execute.

I've manually tested the modified module and it is working.

Issue ticket number and link (if there is one)

Checklist before requesting a review

• I have performed a self-review of my code
• If it is a core feature, I have added thorough tests.
• I have added an entry to CHANGELOG.md
• I have updated the documentation in docs/ (if applicable)