Provide mechanism to validate API keys. Re-organise structure to reflect new responsibility

src/Robware.Auth/API/ApiKeyValidator.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Robware.Auth.API {
+	public class ApiKeyValidator : IApiKeyValidator {
+		private readonly IApiKeys _apiKeys;
+
+		public ApiKeyValidator(IApiKeys apiKeys) {
+			_apiKeys = apiKeys;
+		}
+
+		public async Task<bool> Validate(string key) {
+			try {
+				var apiKey = await _apiKeys.Get(key);
+				return apiKey.Enabled;
+			}
+			catch (ApiKeyNotFoundException) {
+				return false;
+			}
+		}
+	}
+}