Improve login command

[gabryelreyes]

• Login command does not perform a log-in operation but saves login data.
• The command and its arguments are difficult to understand.
• Expiration date is difficult to configure.
• Password can be seen in plain text on the command line.

[gabryelreyes]

@Timuuc I would move this to Milestone v2.0.0 as it depends on #23