Release changes for 4.1.1

[jdeathe]

• Deprecate Makefile target logs-delayed; replaced with logsdef.
• Updates source image to 2.6.1.
• Updates redis40u packages to 4.0.14-2.
• Updates test/health_status helper script with for consistency.
• Updates Makefile target logs to accept [OPTIONS] (e.g make -- logs -ft).
• Updates info/error output for consistency.
• Updates healthcheck failure messages to remove EOL character that is rendered in status response.
• Updates ordering of Tags and respective Dockerfile links in README.md for readability.
• Adds improved test workflow; added test-setup target to Makefile.
• Adds Makefile target logsdef to handle deferred logs output within a target chain.
• Adds exec proxy function to redis-server-wrapper used to pass through nice.
• Adds /docs directory for supplementary documentation.
• Fixes validation failure of 0 second --timeout value in test/health_status.
• Removes ENABLE_REDIS_BOOTSTRAP from docker-compose example configuration.
• Removes ENABLE_REDIS_WRAPPER from docker-compose example configuration.