add support for terminal hyperlinks

[ssbarnea]

I would fine very useful to see links support in blessings, as described at https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda

As you can see that page documents adoptions of this extension across terminals and libraries and it did catch quite fast.

[jquast]

This feature is in blessed, an API-compatible fork of blessings, and documented here, https://blessed.readthedocs.io/en/latest/terminal.html#hyperlinks