Initialise a Scala Play project with a MongoDB controller for Feed Service

What does this MR do?

• Initialises a Scala Play project for the Feed Service
• Adds a MongoDB Controller that abstracts useful MongoDB functions from the Scala Driver for testing.
• Adds dockerisation for the service.

Testing (w/out Docker)

Scala-Play Requirements

To run a Scala Play project locally on Unix system, use the following instruction:

• Download SDKMAN using curl -s "https://get.sdkman.io" | bash
• From the available JDK distributions, download the Amazon Corretto OpenJDK v11.0.18 using sdk install java 11.0.18-amzn
• Ensure it is installed by running java -version, you should see the following:

openjdk version "11.0.18" 2023-01-17 LTS
OpenJDK Runtime Environment Corretto-11.0.18.10.1 (build 11.0.18+10-LTS)
OpenJDK 64-Bit Server VM Corretto-11.0.18.10.1 (build 11.0.18+10-LTS, mixed mode)

• Install sbt with SDKMAN: sdk install sbt

You should now be ready to run a Scala Play application.

MongoDB Perquisites

• Ensure a local MongoDB service is running on your computer (Guide).
• (Optional) Install MongoDB Compass for a simple MongoDB UI.
• Create a database.
• Create a collection.
• Add a few records to the collection.

MongoDB Endpoint Test

• In backend-services/feed-service/MongoTestController, update lines 25-26 with your chosen database/collection names.
• In a terminal, navigate to backend-services/feed-service/
• Run sbt run.
• Navigate to http://localhost:9000/mongo_test.
• A list of the records in collection appear on site.

Testing (with Docker)

• Ensure Docker is installed and running.
• Run the following command in the root directory: docker-compose up --build
• Create a database.
• Create a collection.
• Add a few records to the collection.
• After services load and creating records, navigate to http://localhost:9001/mongo_test.
• A list of the records in collection appear on site.

Relevant issues

Closes #17 (closed). Closes #18 (closed).

backend-services/feed-service/app/models/MongoDBClient.scala

 package models
 
-import com.typesafe.config.ConfigFactory
+import com.typesafe.config.{Config, ConfigFactory}
 
 import org.mongodb.scala.{MongoClient, MongoDatabase, MongoCollection, Document, FindObservable, Observer, Observable}
 import org.mongodb.scala.model.{Filters, Projections, Sorts}
@@ -18,7 +18,11 @@ import scala.util.{Success, Failure, Try}
  */
 class MongoDBClient {
     // Loads the default configuration
-    private val config = ConfigFactory.load()
+    private val applicationConfig: Config = ConfigFactory.load("application.conf")
+    private val referenceConfig: Config = ConfigFactory.parseResources("reference.conf")
+    private val config: Config = referenceConfig.withFallback(applicationConfig).resolve()
+
+    private val mongoUri = config.getString("mongodb.uri")
 
     // Connects to a MongoDB Client when class is constructed
     private var client: MongoClient = this.connect()
@@ -29,7 +33,7 @@ class MongoDBClient {
      * @return A MongoClient instance.
      */
     def connect(): MongoClient = {
-        MongoClient(config.getString("mongo.default.url"))
+        MongoClient(mongoUri)
     }
 
     /**