Configure proxy for API requests and remove hardcoded apiUrl from environment files.

frontend/src/environments/environment.beta.ts

@@ -1,4 +1,3 @@
 export const environment = {
   production: true,
-  apiUrl: 'https://beta.alttd.com',
 };

frontend/src/environments/environment.development.ts

@@ -1,4 +1,3 @@
 export const environment = {
   production: false,
-  apiUrl: 'http://localhost:8080',
 };

frontend/src/environments/environment.production.ts

@@ -1,4 +1,3 @@
 export const environment = {
   production: true,
-  apiUrl: 'https://alttd.com',
 };

frontend/src/environments/environment.ts

@@ -1,4 +1,3 @@
 export const environment = {
   production: true,
-  apiUrl: 'https://alttd.com',
 };