Move mystery set into own module

common/script/src/content/gear/back.js

@@ -1,6 +1,8 @@
 import {translator as t} from '../helpers';
 import events from '../events';
 
+import {back as mysteryBack} from './sets/mystery';
+
 let back = {
   base: {
     0: {
@@ -9,38 +11,7 @@ let back = {
       value: 0
     }
   },
-  mystery: {
-    201402: {
-      text: t('backMystery201402Text'),
-      notes: t('backMystery201402Notes'),
-      mystery: '201402',
-      value: 0
-    },
-    201404: {
-      text: t('backMystery201404Text'),
-      notes: t('backMystery201404Notes'),
-      mystery: '201404',
-      value: 0
-    },
-    201410: {
-      text: t('backMystery201410Text'),
-      notes: t('backMystery201410Notes'),
-      mystery: '201410',
-      value: 0
-    },
-    201504: {
-      text: t('backMystery201504Text'),
-      notes: t('backMystery201504Notes'),
-      mystery: '201504',
-      value: 0
-    },
-    201507: {
-      text: t('backMystery201507Text'),
-      notes: t('backMystery201507Notes'),
-      mystery: '201507',
-      value: 0
-    }
-  },
+  mystery: mysteryBack,
   special: {
     wondercon_red: {
       text: t('backSpecialWonderconRedText'),