cmake: extensions: Add zephyr_topological_sort()

This function performs topological sorting of CMake targets. Its initial
use case in Zephyr will be for implementing sysbuild image dependencies,
i.e., specifying an image order for CMake configuration and flashing.

Sourced from a comment on PR #57884 (anchor: #discussion_r1206807021)

Authored-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
Signed-off-by: Grzegorz Swiderski <grzegorz.swiderski@nordicsemi.no>