Support custom date/time formats

[harpchad]

Allow the user to configure the date/time formatting. Possibly offer a few pre-defined options and try anything else as a go time format string?

Formats:

• EU: "02/01/2006 15:04:05"
• US: "01/02/2006 15:04:05"
• ISO8601: "2006-01-02 15:04:05"
• "20060102 150405"

example: --timefmt=US --timefmt=ISO8601 --timefmt="20060102 150405"

[Macmod]

Great idea! 🥇 I'll review the PR 😃

[Macmod]

Merged 👍