suppressing of secrets in complex JSON serializable types

[zan-mateusz]

Sanitizer.java

• add a method to parse a JSON object from JSON string and suppress the JSON data if needed
• maintains the current behavior otherwise
• added unit tests as needed

ShellEnvironmentSerializer.java

• handles JSON/YAML string passed in the effector invoked. Previously this would just return the string value as is, leaving the sensitive data unsuppressed
• added unit tests as needed