Implement Mongo Seeder v2

What does this MR do?

Adds seeding to User and Questions databases with following env variables to control it:

• ENABLE_QUESTION_DB_SEEDING.
• ENABLE_USER_DB_SEEDING.

Testing

• Ensure ENABLE_QUESTION_DB_SEEDING is set to true in docker-compose.
• Ensure ENABLE_USER_DB_SEEDING is set to true in docker-compose.
• Ensure Docker's MongoDB instances have no documents in Users and Questions DBs.
• Run docker compose up --build.
• Login as with username 'admin' and password 'password'.
• Question appears on page.

Relevant issues

Fixes missing seeding.

backend-services/user-service/server.js

@@ -29,7 +29,8 @@ connect().then(async () => {
         // Database Seeding
         if (process.env.ENABLE_USER_DB_SEEDING) {
             try {
-                const hashedPassword = await bcrypt.hash("password", 10);
+                const password = process.env.SEEDED_ADMIN_PASSWORD
+                const hashedPassword = await bcrypt.hash(password, 10);
             
                 const admin = new UserModel({
                     username: "admin",