Winrm server certgen command

Install certificate to the store, create winrm listener.
@adamedx,  we were supposed to remove --winrm-cert-path from "knife windows cert install --winrm-cert-path cert.pfx" and have only "knife windows cert install cert.pfx".

Here "cert.pfx" is the location of the certificate. So, the command may also look like  "knife windows cert install ../../cert.pfx".

Currently we are supporting both commands:

1. knife windows cert install ../../cert.pfx

2. knife windows cert install --cert-path ../../cert.pfx

Let us know if you want --winrm-cert-path option to be removed completely.