west: zephyr_module: Improved error messaging during west failures

Fixes: #15664

This commit improve error messaging in case `west` list fails.
Previously any error messages and stack trace reported by `west` will
was thrown away by zephyr_module.py.

Now the error, as well as any stack traces, printed by `west` will be
re-printed to the user.

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