Display created ProcessId using wmiexec.py

[NtAlexio2]

This PR contains two changes in wmiexec.py:

1. drops python2 support due to recent changes in Impacket.
2. display ProcessId and ReturnValue for created process using wmi, if -nooutput was specified.

Sample:

┌──(kali㉿kali)-[~/Dev/impacket]
└─$ python examples/wmiexec.py -nooutput Administrator:SecretPass123@192.168.1.78 notepad
Impacket v0.12.0 - Copyright Fortra, LLC and its affiliated companies

[abstract]
class __PARAMETERS
{
        [Out(True)]
        [MappingStrings(['Win32API|Process and Thread Functions|CreateProcess|lpProcessInformation|dwProcessId'])]
        [ID(3)]
        uint32 ProcessId = 6560

        [out(True)]
        uint32 ReturnValue = 0


}