GTI Gateway

Refactor configuration handling to use JSON instead of YAML - Updated the ValueNormalizer to handle invalid maxLength gracefully. - Removed YamlDotNet package reference from the project file. - Enhanced GtiApiClient to sanitize sensitive fields in logs and responses. - Modified ISecretStore documentation to reflect JSON configuration. - Cleaned up DbConnectionFactory by removing legacy code related to DatabaseConfig. - Adjusted Program.cs to provide guidance for JSON configuration file usage. - Updated CheckSecretsCommand and StoreSecretsCommand to work with JSON config files. - Refined GatewayRunner to sanitize API response logs and summarize them effectively. - Updated upgrade-service.ps1 to reflect new JSON configuration file names.