Update Docker configs

[godrei]

Checklist

• I've read and followed the Contribution Guidelines
• README.md is updated with the changes (if needed)

Version

Requires a MAJOR/MINOR/PATCH version update

Context

This PR updates the outdated Docker config files and improves the bitrise setup command logs because the current output hides important details about potential setup failures.

The tool version command error log contains relevant details about the failure:

From this: ... Stepman failed to install: run stepman -version
to this: ... Stepman failed to install: run 'stepman -version' failed: fork/exec /root/.bitrise/tools/stepman: exec format error

Different logs are printed if a Bitrise tool is not installed and for version mismatch.

From this: No supported envman version found
to this: envman isn't installed or Incompatible stepman version (0.0.0-development), minimum version: 0.16.3

Changes

• Update checkIsBitriseToolInstalled logs and error messages
• Modernise Docker config files