added skeleton for webhook page

docs/Webhook.md

@@ -0,0 +1,86 @@
+# Webhook
+
+Comming soon.
+See [https://github.com/jomjol/AI-on-the-edge-device/pull/3163](https://github.com/jomjol/AI-on-the-edge-device/pull/3163) and [https://github.com/jomjol/AI-on-the-edge-device/pull/3174](https://github.com/jomjol/AI-on-the-edge-device/pull/3174)
+
+@RaHehl Please add some explanations.
+Also I think it would be great to add the PHP examples:
+```PHP
+<?php
+$expectedApiKey = 'testtest2';
+
+$receivedApiKey = isset($_SERVER['HTTP_APIKEY']) ? $_SERVER['HTTP_APIKEY'] : '';
+
+if ($receivedApiKey !== $expectedApiKey) {
+    http_response_code(403); // 403 Forbidden
+    echo json_encode(['status' => 'error', 'message' => 'Invalid API key']);
+    exit;
+}
+
+$method = $_SERVER['REQUEST_METHOD'];
+
+if ($method === 'POST') {
+    // Handle POST request: Write data to CSV
+    $csvFile = 'webhook_log.csv';
+
+    $jsonData = file_get_contents('php://input');
+
+    $dataArray = json_decode($jsonData, true);
+    if (!$jsonData || !is_array($dataArray)) {
+        http_response_code(400); // 400 Bad Request
+        echo json_encode(['status' => 'error', 'message' => 'Invalid JSON data']);
+        exit;
+    }
+
+    $csvHandle = fopen($csvFile, 'a');
+    if ($csvHandle === false) {
+        http_response_code(500); // 500 Internal Server Error
+        echo json_encode(['status' => 'error', 'message' => 'Unable to open CSV file']);
+        exit;
+    }
+
+    foreach ($dataArray as $data) {
+        $csvRow = [
+            $data['timestamp'], 
+            $data['name'], 
+            $data['rawValue'], 
+            $data['value'], 
+            $data['preValue'], 
+            $data['rate'], 
+            $data['changeAbsolute'], 
+            $data['error']
+        ];
+        fputcsv($csvHandle, $csvRow);
+    }
+
+    fclose($csvHandle);
+
+    http_response_code(200); // 200 OK
+    echo json_encode(['status' => 'success', 'message' => 'Data written to CSV file']);
+} elseif ($method === 'PUT') {
+    // Handle PUT request: Save image
+    $imageFilePath = 'uploaded_image.jpg';
+
+    $imageData = file_get_contents('php://input');
+
+    if (!$imageData) {
+        http_response_code(400); // 400 Bad Request
+        echo json_encode(['status' => 'error', 'message' => 'No image data received']);
+        exit;
+    }
+
+    if (file_put_contents($imageFilePath, $imageData) === false) {
+        http_response_code(500); // 500 Internal Server Error
+        echo json_encode(['status' => 'error', 'message' => 'Unable to save the image']);
+        exit;
+    }
+
+    http_response_code(200); // 200 OK
+    echo json_encode(['status' => 'success', 'message' => 'Image uploaded successfully']);
+} else {
+    // Handle unsupported HTTP methods
+    http_response_code(405); // 405 Method Not Allowed
+    echo json_encode(['status' => 'error', 'message' => 'Method not allowed']);
+}
+?>
+```

docs/nav.yml

@@ -52,6 +52,7 @@ nav:
       - REST-API.md
       - MQTT-API.md
       - Influx-DB.md
+      - Webhook.md
       # - ...
 
   - Development: