Add logging framework with Logger, LoggerFactory, and appenders

- Introduced ILogger interface for logging methods
- Implemented Logger class with various logging levels and message formatting
- Created LoggerFactory for managing logger instances and appender configuration
- Added LoggingLevel enum and mapping for logging level types
- Developed ConsoleAppender and TechnikerMeAppender for different logging outputs
- Implemented appender management with AppenderFactory and base Appender class
- Established Threshold class for controlling logging levels

src/logger/Threshold.ts

@@ -0,0 +1,19 @@
+import Defaults from '../Defaults';
+import { Subject } from '../lang/observables';
+import { LoggingLevel } from './LoggingLevel';
+
+export class Threshold {
+  private _threshold: Subject<LoggingLevel>;
+
+  constructor(loggingLevel?: LoggingLevel) {
+    this._threshold = new Subject(loggingLevel ?? Defaults.loggingLevel);
+  }
+
+  set value(value: LoggingLevel) {
+    this._threshold.value = value;
+  }
+
+  get value(): LoggingLevel {
+    return this._threshold.value;
+  }
+}