Speed up open port detection by running the checks as a single command

[bsideup]

While working on #1781 (and it is all about the ultra fast tests) I noticed that the port checks take quite some time.

This change will:

1. Make external port checks run in parallel
2. Make internal port checks run as a single docker exec command rather than NUM_PORTS * NUM_STRATEGIES commands (3, 6, 9...)

Measurements

Even for 1 port, it is:

Before (1,443ms):

22:32:02.699 INFO  🐳 [nginx:1.9.4] - Creating container for image: nginx:1.9.4
22:32:02.875 INFO  🐳 [nginx:1.9.4] - Starting container with ID: 28a8774b9f299851811fcd8bc900910f9a6cf148c95aa88bc3b57d69f0f50939
22:32:03.562 INFO  🐳 [nginx:1.9.4] - Container nginx:1.9.4 is starting: 28a8774b9f299851811fcd8bc900910f9a6cf148c95aa88bc3b57d69f0f50939
22:32:03.583 DEBUG org.testcontainers.containers.ExecInContainerPattern - /interesting_knuth: Running "exec" command: /bin/sh -c cat /proc/net/tcp{,6} | awk '{print $2}' | grep -i :1f90
22:32:03.767 DEBUG org.testcontainers.containers.ExecInContainerPattern - /interesting_knuth: Running "exec" command: /bin/sh -c nc -vz -w 1 localhost 8080
22:32:03.950 DEBUG org.testcontainers.containers.ExecInContainerPattern - /interesting_knuth: Running "exec" command: /bin/bash -c </dev/tcp/localhost/8080
22:32:04.142 INFO  🐳 [nginx:1.9.4] - Container nginx:1.9.4 started

After (1,060ms):

22:31:27.313 INFO  🐳 [nginx:1.9.4] - Creating container for image: nginx:1.9.4
22:31:27.497 INFO  🐳 [nginx:1.9.4] - Starting container with ID: 2ab798d807aed3dc15afead9ff7aef82e6ff5f95087d9bf1866893f5587cf553
22:31:28.180 INFO  🐳 [nginx:1.9.4] - Container nginx:1.9.4 is starting: 2ab798d807aed3dc15afead9ff7aef82e6ff5f95087d9bf1866893f5587cf553
22:31:28.204 DEBUG org.testcontainers.containers.ExecInContainerPattern - /flamboyant_chaum: Running "exec" command: /bin/sh -c true &&  (cat /proc/net/tcp{,6} | awk '{print $2}' | grep -i :1f90 || nc -vz -w 1 localhost 8080 || /bin/bash -c '</dev/tcp/localhost/8080')
22:31:28.373 INFO  🐳 [nginx:1.9.4] - Container nginx:1.9.4 started

[bsideup]

waitStrategyTarget.getContainerInfo() will call Docker API in case of Docker Compose, and, if debug is disabled, it is unnecessary