Add support for Host definitions in ssh_config

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
```

Replaced iteritems deprecated function with items

Added default path for sftp Subsystem in FreeBSD

Added configuration options for ssh_config

Made a small change to reflect the default sshd_config

The default value for ServerKeyBits is 1024 both upstream and in distros

Use iteritems() instead of items().

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

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

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

add options to give a key size to generate_key

Adds support to customize /etc/ssh/moduli file

adds support to harden sshd_config (KeyExchange, Ciphers, MACs)

Stop messing up the first line in ssh_known_hosts

Fix service name for Arch Linux

Add option to remove ssh_host_keys

Improve default lookup

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

Fix mine_function example in pillar.example

This fixes #34, salt version 2015.5.x needs an extra argument
for shell routines.

added the missing ":" and delete the redundant lines

Fix bug that added : at the end of the key

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

add gentoo support

Refactor auth.sls to allow more keys for one user

Added AllowUsers,AllowGroups,DenyUsers,DenyGroups

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

add ed25519 host key type; add AuthenticationMethods option

added archlinux support to openssh map.jinja

Add support for ed25519 host keys