Add Friend service

What does this MR do?

Adds the friend service. Adds the endpoints from the swagger contacts

Relevant screenshots

(Add any relevant screenshots of MR's functionality)

Testing

Look at swagger for testing

Relevant issues

(List the relevant issues, i.e. Closes #...)

backend-services/friend-service/src/Database/Schemas/FriendSchema.ts

+import mongoose, { Schema } from 'mongoose'
+
+/**
+ * Schema for representing an a friend
+ */
+const FriendSchema = new Schema({
+  User1: {
+    type: String,
+    required: true
+  },
+  User2: { 
+    type: String,
+    required: true
+  }
+})
+
+export default FriendSchema;
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