Surface current user, computer, and local IP information

Expose basic local system identity information through the existing System module so ObjoBasic apps can identify the current operating-system user, the computer name, and active local IP addresses.

Requested API:

• System.Username As String
• System.ComputerName As String
• System.LocalIPAddresses As Array(Of String)
• System.LocalIPv4Addresses As Array(Of String)
• System.LocalIPv6Addresses As Array(Of String)

The IP address API deliberately returns arrays because modern machines commonly have multiple network interfaces and address families.