This set of options reflect the ssh_config options that are set by
default on Debian. The way this was set before has the potential to
break exisisting setups that rely on "normal" defaults, rather than the
rather opinionated ones that are now being shipped with this formula.

put the ssh_config Host:* options in the defaults file so they can be overridden

This gives us the ability to define system-wide definitions for specific Hosts, and their options.

For example, with this in pillar:

```
# this is the place for host-wide SSH config
ssh_config:
  ...
  Hosts:
    # this simplifies cloning with custom params
    # eg: git clone my-git:foo/bar
    my-git:
      User: git
      HostName: git.example.com
      Port: 2222
```

This would add a section in `/etc/ssh/ssh_config`:

```
Host my-git
    User git
    HostName git.example.com
    Port 2222
```

Signed-off-by: POTIER Mathieu <mathieu.potier@onzeway.eu>

Signed-off-by: POTIER Mathieu <mathieu.potier@onzeway.eu>

Made a small change to reflect the default sshd_config

Signed-off-by: René Jochum <rene@jochums.at>

Signed-off-by: René Jochum <rene@jochums.at>

Added defaults.yaml and map.jinja similar to template-formula and salt-formula

This state manages /etc/ssh/ssh_known_hosts and fills it with
public SSH host keys of other minions.

This will add more options to set to secure openssh
- AllowUsers
- AllowGroups
- DenyUsers
- DenyGroups

Correct indentation

When specifying multiple unknown ssh options, they would all appear on
the same line.

By not specifying it, root user's group should be used.