feat(backend): Added endpoint to fetch HTML version of learning object (from Dwengo backend)

Also refactored a bit to make this easier.

backend/src/util/apiHelper.ts

@@ -8,17 +8,21 @@ import axios, { AxiosRequestConfig } from 'axios';
  *
  * @param url The API endpoint to fetch from.
  * @param description A short description of what is being fetched (for logging).
- * @param params
+ * @param options Contains further options such as params (the query params) and responseType (whether the response
+ *                should be parsed as JSON ("json") or whether it should be returned as plain text ("text")
  * @returns The response data if successful, or null if an error occurs.
  */
 export async function fetchWithLogging<T>(
     url: string,
     description: string,
-    params?: Record<string, any>
+    options?: {
+        params?: Record<string, any>,
+        query?: Record<string, any>,
+        responseType?: "json" | "text",
+    }
 ): Promise<T | null> {
     try {
-        const config: AxiosRequestConfig = params ? { params } : {};
-
+        const config: AxiosRequestConfig = options || {};
         const response = await axios.get<T>(url, config);
         return response.data;
     } catch (error: any) {

backend/src/util/envvars.ts

@@ -11,6 +11,8 @@ export const EnvVars: { [key: string]: EnvVar } = {
     DbUsername: { key: DB_PREFIX + 'USERNAME', required: true },
     DbPassword: { key: DB_PREFIX + 'PASSWORD', required: true },
     DbUpdate: { key: DB_PREFIX + 'UPDATE', defaultValue: false },
+    LearningContentRepoApiBaseUrl: { key: PREFIX + "LEARNING_CONTENT_REPO_API_BASE_URL", defaultValue: "https://dwengo.org/backend/api"},
+    FallbackLanguage: { key: PREFIX + "FALLBACK_LANGUAGE", defaultValue: "nl" },
 } as const;
 
 /**