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/utils/ConfigHelper.scala

@@ -4,6 +4,10 @@ import com.typesafe.config.{Config, ConfigFactory}
 
 object ConfigHelper {
   private val applicationConfig: Config = ConfigFactory.load("application.conf")
+  private val referenceConfig: Config = ConfigFactory.parseResources("reference.conf")
+  private val config: Config = referenceConfig.withFallback(applicationConfig).resolve()
 
-  def getString(key: String): String = applicationConfig.getString(key)
+  def getString(key: String): String = config.getString(key)
+  def getInt(key: String): Int = config.getInt(key)
+  def getBoolean(key: String): Boolean = config.getBoolean(key)
 }