cli: add config option for built-in pager's ruler

[Samasaur1]

Checklist

If applicable:

• I have updated CHANGELOG.md
• I have updated the documentation (README.md, docs/, demos/)
• I have updated the config schema (cli/src/config-schema.json)
• I have added tests to cover my changes

[yuja]

Thanks.

[rwjblue]

Please excuse my ignorance here, what does the ruler do? It's not immediately obvious upon reading the docs here (though maybe if I knew the underlying tools better it would be clearer).

[Samasaur1]

Please excuse my ignorance here, what does the ruler do? It's not immediately obvious upon reading the docs here (though maybe if I knew the underlying tools better it would be clearer).

The ruler is what streampager calls the one-line-tall gray bar at the bottom of the screen that shows your progress through the file and a couple other things (whether the pager is waiting for more data, I think?). You can always toggle it with control-R, but you couldn't configure it to start disabled even though streampager itself has an option to do so

[rwjblue]

Thank you!