Add new Backend structure with proper .NET 8 projects

src/Backend/DiunaBI.WebAPI/diunabi-admin-firebase.json

@@ -0,0 +1,13 @@
+{
+  "type": "service_account",
+  "project_id": "#{firebase-project-id}#",
+  "private_key_id": "#{firebase-private-key-id}#",
+  "private_key": "#{firebase-private-key}#",
+  "client_email": "#{firebase-client-email}#",
+  "client_id": "#{firebase-client-id}#",
+  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
+  "token_uri": "https://oauth2.googleapis.com/token",
+  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
+  "client_x509_cert_url": "#{firebase-client-cert-url}#",
+  "universe_domain": "googleapis.com"
+}