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/appenders/Appender.ts

@@ -0,0 +1,63 @@
+import {LoggingLevel, type LoggingLevelType} from '../LoggingLevel';
+import type ILogMessage from './LogMessage';
+
+export type AppenderOptions = {
+  domain?: string;
+};
+
+export default class Appender {
+  private readonly _logRecorderUrl: string = 'https://logserver.techniker.me/api/logs';
+  // @ts-ignore
+  private readonly _domain: string = typeof globalThis !== 'undefined' ? (globalThis.location?.hostname ?? '') : '';
+  private readonly _logMessageQueue: ILogMessage[] = [];
+  private _pendingPostLogMessagePromise: Promise<Response | undefined> | undefined = undefined;
+
+  constructor(logRecorderUrl: string, {domain}: AppenderOptions) {
+    this._logRecorderUrl = logRecorderUrl;
+    this._domain = domain ?? this._domain;
+  }
+
+  public log(timestamp: string, level: LoggingLevelType, category: string, message: string): void {
+    const logMessage = {
+      timestamp,
+      domain: this._domain,
+      level,
+      category,
+      message
+    };
+    this.queueMessage(logMessage);
+    this.postLogMessage();
+  }
+
+  private async postLogMessage(): Promise<void> {
+    const logMessage = this._logMessageQueue.shift();
+
+    if (!logMessage || this._pendingPostLogMessagePromise !== undefined) {
+      return;
+    }
+
+    try {
+      if (typeof fetch === 'undefined') {
+        console.error('Fetch API is not available in this environment');
+        return;
+      }
+
+      this._pendingPostLogMessagePromise = fetch(this._logRecorderUrl, {
+        headers: {
+          'Content-Type': 'application/json',
+          Accept: 'application/json'
+        },
+        mode: 'no-cors',
+        method: 'POST',
+        body: JSON.stringify(logMessage)
+      }).then(() => (this._pendingPostLogMessagePromise = undefined));
+    } catch (e) {
+      console.error('Unable to send logs due to [%o]', e);
+      return;
+    }
+  }
+
+  private queueMessage(logMessage: ILogMessage): void {
+    this._logMessageQueue.push(logMessage);
+  }
+}