Line height should be configurable

[colemickens]

I really love cosmic-term. I think y'all are using a custom renderer, but wow does the text look great compared to my otherwise-normal-daily-driver Alacritty.

however, the line height seems a bit high. There are are a number of applications that render graphics or text in a way where it's noticeable that cosmic-term's line height is taller than other terminal applications.

It would be great if it were customizable, or generally lower by default to match other terms and the expectations of some TUI applications.