Use text not images for screenshots

[samuelcolvin]

pgcli is awesome. Thank you.

Would be very useful (and better for SEO) if the screens on / and /features where text (with html to style them) not images.

This would allow searching and copy & paste.

I realise that some of the screenshots include the drop-down context manager which might not be possible to capture in html, but the rest shouldn't be too hard.

See https://python-devtools.helpmanual.io/ for an example of what's possible without too much trouble.

[meeuw]

Hmm we could also use https://asciinema.org/ ?