Reduce logs in EnvironmentAndSystemPropertyClientProviderStrate…

[rnorth]

Remove logs in EnvironmentAndSystemPropertyClientProviderStrategy which risk leaking credentials on console output

Fixes #1912

Before this change, docker registry credentials could be logged:

• if credentials were hardcoded in ~/.docker/config.json and
• if Testcontainers detected environment variables/system properties (such as DOCKER_HOST) which set/override the address of the docker daemon.

We recommend that you check recent CI logs for any accidentally logged credentials, and apologise for the inconvenience. Please see below for an example of the log message, which occurs during initial connection to the Docker daemon.

INFO  o.t.d.DockerClientProviderStrategy - Found Docker environment with Environment 
variables, system properties and defaults. Resolved: 
    dockerHost=unix:///var/run/docker.sock
    apiVersion='{UNKNOWN_VERSION}'
    registryUrl='https://index.docker.io/v1/'
    registryUsername='...'
    registryPassword='...'
    registryEmail='...'
    dockerConfig='DefaultDockerClientConfig[dockerHost=
unix:///var/run/docker.sock,registryUsername=...,registryPassword=<...>,
registryEmail=<...>,registryUrl=https://index.docker.io/v1/,
dockerConfigPath=/home/user/.docker,sslConfig=<null>,
apiVersion={UNKNOWN_VERSION},dockerConfig=<null>]'

has been changed to:

INFO  o.t.d.DockerClientProviderStrategy - Found Docker environment with Environment 
variables, system properties and defaults. Resolved dockerHost=unix:///var/run/docker.sock