New domain wizard: passphrase dialog should offer password text field to enter passphrase (not default text field)

When you create a new domain in the openshift wizard, you may create a new domain if you have no domain on openshift so far. The appropriate dialog asks you to provide the domain name and a ssh key. If you have no ssh key so far, you may create a new one. You'd then of course have to provide a pass phrase for your key. The passphrase shall be entered in a text field. This text field currently is a default text field that shows you what you type.

We should replace this text field by a password text field which shows "*" instead of the real characters you type.