feat(content): December 2023 Content (#15023)

* feat(content): add December subscriber items, backgrounds, and enchanted armoire

* feat(content): correct item slot for armoire, change release dates for testing

* fix(backgrounds): correct start date

* fix(armoire): Add canonical start date

* fix(test): only count released items

---------

Co-authored-by: Sabe Jones <sabrecat@gmail.com>
Co-authored-by: SabreCat <sabe@habitica.com>

website/common/script/content/appearance/backgrounds.js

@@ -592,6 +592,11 @@ const plannedBackgrounds = {
     barrel_cellar: { },
     autumn_tree_tunnel: { },
   },
+  backgrounds122023: {
+    holiday_tree_forest: { },
+    ice_sculpture_festival: { },
+    winter_full_moon: { },
+  },
   eventBackgrounds: {
     birthday_bash: {
       price: 0,
@@ -637,6 +642,7 @@ const plannedBackgrounds = {
 const releaseDates = {
   backgrounds102023: '2023-10-10T08:00-04:00',
   backgrounds112023: '2023-11-07T08:00-05:00',
+  backgrounds122023: '2023-12-05T08:00-05:00',
 };
 
 const flat = {};