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/feed-service/app/repositories/QuestionRepository.scala

@@ -29,3 +29,22 @@ class QuestionRepository extends Repository[Question] (
         })
     }
 }
+
+object QuestionRepository {
+    def seedDatabase(): Unit = {
+        println("Seeding Question Database...")
+
+        try {
+            Question.createQuestionAsync("Who is there?")
+            Question.createQuestionAsync("How is that there?")
+            Question.createQuestionAsync("Where is there?")
+
+            println("Successfully seeded Question Database!")
+        } catch {
+            case ex: Throwable => {
+                println("Error seeding Question Database...")
+                println(ex)
+            }
+        }  
+    } 
+}