Intelligent prompt truncation

Feature Request

As has been discussed a few times, it would be great if Starship could handle its own prompt truncation, instead of offloading that responsibility to the shell. Making use of $COLUMNS we could intelligently truncate "less important" information from the prompt, making modules more concise, until they eventually have to be removed.

Is your feature request related to a problem? Please describe.

Currently, on small enough terminal windows, the prompt is either truncated by the shell (#2445), or breaks into the next line.

Describe the solution you'd like

As the window gets smaller, we can begin by hiding language runtime version numbers, only showing their symbol, we could hide joining words between modules, or we could truncate the PWD directory.