Add support for `z-output`

[cipriancraciun]

Just like there is z-input and z-select to allow easy input, there should be a z-output to allow easy output.

Here are some output modes:

• log / transcript (levels, slugs, code, message);
• (Linux DBUS) notification support (https://github.com/TheCreeper/go-notify);
• SMTP;
• Discord;
• Slack;

Here are some cross-cutting concerns:

• fmt.Sprintf like formatting;
• QRCode (especially on the terminal), useful for links (https://github.com/mdp/qrterminal);
• pause for some time;
• pause for keypress;