Add seed-fetching service

ALttPRandomizer/Service/SeedService.cs

@@ -0,0 +1,25 @@
+namespace ALttPRandomizer.Service {
+    using ALttPRandomizer.Azure;
+    using System;
+    using System.Collections.Generic;
+    using System.Threading.Tasks;
+
+    public class SeedService {
+        public SeedService(AzureStorage azureStorage) {
+            this.AzureStorage = azureStorage;
+        }
+
+        private AzureStorage AzureStorage { get; }
+
+        public async Task<IDictionary<string, string>> GetSeed(string seedId) {
+            var files = await this.AzureStorage.GetFiles(seedId);
+
+            var result = new Dictionary<string, string>();
+            foreach (var file in files) {
+                result[file.Key] = Convert.ToBase64String(file.Value.ToMemory().ToArray());
+            }
+
+            return result;
+        }
+    }
+}