Adding winrm certgen support

(cherry picked from commit f1b5ba49f55784b48c68e421e364ce2fa6068970)

Conflicts:
	lib/chef/knife/winrm.rb
Added new winrm commands and rspec tests for the new commands
Fixed rspec tests
Incorporated review comments related to winrm listener,cert and passphrase
Changes to rename winrm certgen commands

Conflicts:
Fixed bugs
Fixed failing rspecs
Updated options related to winrm cert generate,listener create,cert install to add 'winrm_ prefix
Merge pull request #2 from ClogenyTechnologies/sid-winrm-prefix-cert-gen-option

Update command options to use 'winrm_' prefix
made --winrm-cert-path optional for 'knife windows cert install' command
Added msg specifying which certificates contain private key
Merge pull request #3 from ClogenyTechnologies/nim/winrm-cert-cmd-changes

Implement code review feedback for winrm cert-related subcommands
renamed winrm-cert-passphrase and winrm-thumbprint
removed winrm_cert_path option
Fixed unit testcases that fail due to changes in Chef 12
Adding winrm certgen support

(cherry picked from commit f1b5ba49f55784b48c68e421e364ce2fa6068970)

Conflicts:
	lib/chef/knife/winrm.rb
Added new winrm commands and rspec tests for the new commands
Fixed rspec tests
Incorporated review comments related to winrm listener,cert and passphrase
Changes to rename winrm certgen commands

Conflicts: