Sidecar logs error to pull sleepers during tests/integration/computation/test_computation

[pcrespov]

Steps to reproduce:

• Run tests/integration/computation/test_computation.py::test_start_pipeline
• When services/web/server/src/simcore_service_webserver/computation_handlers.py::start_pipeline is called,
  the sidecar log shows a failure

**I guess the problem is that unsecured access to the registry is not allowed? ** Shall we add a certificate during testing? But, why the fixture allows to push/pull a sleeper test image though?? Is it because
The test succeeds because it does not check errors in the logs of sidecar

[sanderegg]

this is a known issue and is due to the fact the registry is insecured.

to alleviate this:

• secure the registry, or
• set the registry as allowed insecure registry in the /etc/docker/daemon.json

[sanderegg]

shall we close this @pcrespov ?