tests/docker: add USER stanzas to non-lci images

These are flat but not generated by lcitool so we need to manually
update them with the `useradd` stanza.

Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230228190653.1602033-20-alex.bennee@linaro.org>
20 files changed