Core/Player: Implemented account wide mounts

Closes #17369

sql/updates/auth/6.x/2016_10_01_00_auth.sql

@@ -0,0 +1,10 @@
+--
+-- Table structure for table `battlenet_account_mounts`
+--
+DROP TABLE IF EXISTS `battlenet_account_mounts`;
+CREATE TABLE `battlenet_account_mounts` (
+  `battlenetAccountId` int(10) unsigned NOT NULL,
+  `mountSpellId` int(10) unsigned NOT NULL,
+  `flags` tinyint(3) unsigned NOT NULL DEFAULT '0',
+  PRIMARY KEY (`battlenetAccountId`,`mountSpellId`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8;