Implement the new cryptographic interface ( Gatekeeper )

Necessary to make sure the saved encrypted passwords are decipherable
during next script execution and also implements the password in a
way that makes the app unusable under different user account or on a
different computer
CLI - instantiate the main application's controller (App) on new
CLI - use actual values from config for the severity option
CLI - preserve context in the options' callbacks
CLI - implement the encrypt command
Improve whitespace
CLI - implement the --verbosity option
Improve whitespace
Add missing docblock to Cli.encrypt()