Refactor logging level handling and remove example usage

* Updated `CommandLineOptions` and `ConfigurationObject` to use `LoggingLevel` type instead of string for log levels.
* Modified `LoggerFactory` to set logging levels using the new `LoggingLevelMapping` methods.
* Removed the `example-usage.ts` file as it was no longer needed.
* Adjusted `Threshold` class to simplify logging level management.

test/logger/LoggingLevel.ts

@@ -37,21 +37,21 @@ export class LoggingLevelMapping {
 
   public static convertLoggingLevelTypeToLoggingLevel(level: LoggingLevelType): LoggingLevel {
     switch (level) {
-      case 'Off':
+      case 'off':
         return LoggingLevel.Off;
-      case 'Fatal':
+      case 'fatal':
         return LoggingLevel.Fatal;
-      case 'Error':
+      case 'error':
         return LoggingLevel.Error;
-      case 'Warning':
+      case 'warning':
         return LoggingLevel.Warning;
-      case 'Info':
+      case 'info':
         return LoggingLevel.Info;
-      case 'Debug':
+      case 'debug':
         return LoggingLevel.Debug;
-      case 'Trace':
+      case 'trace':
         return LoggingLevel.Trace;
-      case 'All':
+      case 'all':
         return LoggingLevel.All;
       default:
         throw new Error(`[LoggingLevelMapping] Received unknown logging level type [${level}]`);