Scenario: Crew pod, some attached science, and a landing stage (tank + motor only, no legs). You want to use the remaining engine/fuel for braking etc but you don't want/need to land it (it's literally in the way).

LG needs an option to obey staging to /reach/ chutes or landing gears, so that it will discard any remaining lower stages/fairings etc prior to trying to use them (and possibly for it's landing predictions).

Dup of everything compiled in #1052