Remove hardcoded passwords from templates

[larsks]

Is this a BUG REPORT or FEATURE REQUEST?:

Uncomment only one, leave it on its own line:

/kind bug

/kind enhancement

What happened:

The templates configure vms to use password authentication, and include a hardcoded passwords. There are two separate security concerns here:

• Setting a default password means that people will start vms with that default configuration. If they are connected to a routeable network, they will rapidly be compromised.
• Passwords of any sort are vulnerable to brute force attempts

What you expected to happen:

I would expect the templates to have a template parameter for an SSH public key.