scripts: zephyr modules: introducing Zephyr module dependency handling

This commit introduces the possibility of adding dependencies between
Zephyr modules to ensure that a Zephyr module on which other modules
depends is processed first.

The dependency chain is ordered using a topological sort.

This allows to add dependencies to a zephyr/module.yml as:

build:
  cmake: .
  depends:
    - fatfs

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>