Reduce Warning messages in case a Docker image cannot be found

[ckunki]

In case a Docker image cannot be found, the ITDE currently prints long warnings which are distracting and make it hard to analyze problems in the logs displayed in CI builds.

Sample

WARNING -
AnalyzeTestContainer_d87..._1_DockerTestContainerBuild, no_cache=False): 
Image exaslct_test/buildtestcontainertest:db-test-container_E3U...VLA not in registry, 
got exception 404 Client Error for http+docker://localhost/v1.43/images/create
  ?tag=db-test-container_E3U...VLA
  &fromImage=exaslct_test%2Fbuildtestcontainertest:
Not Found ("pull access denied for exaslct_test/buildtestcontainertest,
repository does not exist or may require 'docker login': 
denied: requested access to the resource is denied")

Proposal

• display a shorter message withlog level WARN by default, e.g.

  Docker image ... does not exist, yet - Building it on the fly

• display full output with log level INFO