refactor(achievements): crush down to much fewer notification types

most work by @CuriousMagpie

website/common/script/content/constants/stableAchievements.js

@@ -0,0 +1,16 @@
+const STABLE_ACHIEVEMENTS = {
+  ACHIEVEMENT_BEAST_MASTER: {
+    masterAchievement: 'beastMasterName',
+    masterNotificationType: 'ACHIEVEMENT_STABLE',
+  },
+  ACHIEVEMENT_MOUNT_MASTER: {
+    masterAchievement: 'mountMasterName',
+    masterNotificationType: 'ACHIEVEMENT_STABLE',
+  },
+  ACHIEVEMENT_TRIAD_BINGO: {
+    masterAchievement: 'triadBingoName',
+    masterNotificationType: 'ACHIEVEMENT_STABLE',
+  },
+};
+
+export default STABLE_ACHIEVEMENTS;