controllers.tracking: move get_flight_path[2] to a global function
controllers.tracking: move get_flight_path[2] to a global function

To be reused.

shadowoneau/skylines,snip/skylines,Turbo87/skylines,Turbo87/skylines,Harry-R/skylines,dkm/skylines,shadowoneau/skylines,Harry-R/skylines,skylines-project/skylines,RBE-Avionik/skylines,TobiasLohner/SkyLines,TobiasLohner/SkyLines,skylines-project/skylines,RBE-Avionik/skylines,skylines-project/skylines,RBE-Avionik/skylines,shadowoneau/skylines,snip/skylines,Turbo87/skylines,skylines-project/skylines,dkm/skylines,Harry-R/skylines,TobiasLohner/SkyLines,dkm/skylines,dkm/skylines,kerel-fs/skylines,RBE-Avionik/skylines,snip/skylines,shadowoneau/skylines,kerel-fs/skylines,Turbo87/skylines,Harry-R/skylines,kerel-fs/skylines