Add ability to enable SSH in context-windows

[lukasfazik]

Description

I have added the enableSSH function to the Windows contextualization package. I'm also calling this function from the contextualization loop.

This function:

• Checks if sshd service is present (OpenSSH.Server capability is installed, or another SSH server is installed).
• If the service is not present, the function ends gracefully
• If the service is running and autostart is enabled, nothing is changed
• If the service is not running, it will be started
• If the service is not set to start automatically, it will be started

Function logs the following events:

• The sshd service is not present
• The sshd service is started and set to start automatically
• The sshd service was started by the function
• The sshd service was set to start automatically by the function

Things to consider

• Add check for new contextualization variable ENABLE_SSH = "NO", so users can disable this behaviour
• Call the function only if SSH needs to be contextualized ( Fix allow inbound echo requests + configure SSH keys only when needed #152 )