Add Option in User Configuration for SSH/SFTP

[tsc]

Currently users that are created cannot SSH or SFTP in because they are not in the required groups.

Configuration options should be added to:

• allow/deny the user to SSH in
• if above is allowed, restrict user to SFTP only

[Max Schaefer]

I need to add this to the user management module.

[tsc]

Fixed in 4e5c05b.