New docs: Convert inline example code to use codeinclude macro

Improvement for the new mkdocs-based documentation.

Aim to replace the majority of inline code blocks in the docs with codeinclude macros, so that our examples are compiled and tested as part of the build.

This doesn't need to all be done in one PR - it probably ought to be split.

Pages that would benefit from this (in no particular order):

• docs/features/container_logs.md
• docs/features/commands.md
• docs/features/creating_container.md
• docs/features/creating_images.md
• docs/features/files.md
• docs/modules/docker_compose.md
• docs/modules/elasticsearch.md
• docs/modules/kafka.md
• docs/modules/vault.md
• docs/modules/webdriver_containers.md
• docs/test_framework_integration/junit_4.md
• docs/test_framework_integration/junit_5.md
• docs/test_framework_integration/spock.md
• docs/supported_docker_environment/logging_config.md