Updated 'configuring an ide' document for CLion.

[jwmcgettigan]

I had a hard time configuring CLion following the existing guide so I've made some improvements that hopefully make it easier to read and understand. As this is a pretty large overhaul of the document, I'd love if anyone else who uses CLion to develop the Godot engine could review.

I've made sure to walk through and verify the entirety of the guide but it would be great to have somebody walk through the guide in a different environment than mine (Windows 10).

I also plan to look into https://github.com/godotengine/godot-docs/issues/6495.