Now pre-compiles age group metadata instead of generating it on every query (#235)

* Server will now quit on start up if schema updates fail (closes Abort start up if an error occurs during database upgrade #221)

* Moved AgeGroups to it's own class

* Improved query performance by defining the AgeGroupId as a metadata item. A metadata refresh is required to generate this data

gaseous-server/Support/Database/MySQL/gaseous-1011.sql

@@ -0,0 +1,18 @@
+CREATE TABLE `AgeGroup` (
+  `Id` BIGINT NOT NULL,
+  `GameId` BIGINT NULL,
+  `AgeGroupId` INT NULL,
+  `dateAdded` DATETIME NULL DEFAULT NULL,
+  `lastUpdated` DATETIME NULL DEFAULT NULL,
+  PRIMARY KEY (`Id`));
+
+ALTER TABLE `Game` 
+CHANGE COLUMN `Slug` `Slug` VARCHAR(255) NULL DEFAULT NULL;
+
+CREATE OR REPLACE VIEW `view_Games` AS
+SELECT 
+    a.*, b.AgeGroupId
+FROM
+    view_GamesWithRoms a
+    LEFT JOIN AgeGroup b ON b.GameId = a.Id
+ORDER BY NameThe;