Improve KeyPathResolver class name and JavaDoc clarity

The KeyPathResolver class (internal, package-private) provides three static utility methods for working with Vault secret data:

• resolveKeyPath() - extracts values from secret data
• setNestedValue() - sets values in secret data
• removeNestedValue() - removes values from secret data

Issues:

1. The class name "KeyPathResolver" only describes the read operation, not the write/remove operations
2. The class-level JavaDoc focuses primarily on the resolution logic but doesn't clearly explain the full scope of the class

Suggested improvements:

• Consider renaming to better reflect all operations (e.g., VaultKeyPathOperations, KeyPathManager, or SecretDataNavigator)
• Enhance class-level JavaDoc to:
  • Clearly state this is a utility class for all key path operations (read/write/remove)
  • Explain the relationship between the three methods
  • Clarify that this is an internal utility class

Context:

• This is an internal (package-private) class, so changes won't affect public API
• Reviewer feedback from PR #71: https://github.com/wildfly-security/wildfly-elytron-hashicorp-vault/pull/71
• Current implementation is functionally correct; this is a code clarity improvement