[Enhancement]: Support different docker context

Module

Core

Proposal

% docker context ls
NAME                  DESCRIPTION                               DOCKER ENDPOINT                                  KUBERNETES ENDPOINT                                           ORCHESTRATOR
default               Current DOCKER_HOST based configuration   unix:///var/run/docker.sock                      https://api.xpto.net:6443 (dlovison)   swarm
desktop-linux                                                   unix:///Users/dlovison/.docker/run/docker.sock                                                                 
my-remote-engine2 *                                             ssh://vagrant@192.168.56.6                                       

When I execute my test

16:25:20,932 ERROR (testng-ExampleJdg4931) [org.testcontainers.dockerclient.DockerClientProviderStrategy] Could not find a valid Docker environment. Please check configuration. Attempted configurations were:
16:25:20,932 ERROR (testng-ExampleJdg4931) [org.testcontainers.dockerclient.DockerClientProviderStrategy]     UnixSocketClientProviderStrategy: failed with exception InvalidConfigurationException (Could not find unix domain socket). Root cause NoSuchFileException (/var/run/docker.sock)
16:25:20,933 ERROR (testng-ExampleJdg4931) [org.testcontainers.dockerclient.DockerClientProviderStrategy] As no valid configuration was found, execution cannot continue

Start with the Core module and the DockerClientProviderStrategy errors shown in the issue, especially UnixSocketClientProviderStrategy. Compare the current Docker environment detection with the configurations listed by docker context ls. Done means a selected non-default Docker context can be used instead of requiring /var/run/docker.sock, with the relevant Testcontainers checks passing.