Properly count Blender Sync users

Use a dedicated aggregation pipeline to filter one startup.blend per home project and count them.

cloud/stats/routes.py

@@ -3,7 +3,7 @@ import datetime
 import functools
 
 from flask import Blueprint, jsonify
-from cloud.stats import count_nodes, count_users
+from cloud.stats import count_nodes, count_users, count_blender_sync
 
 blueprint = Blueprint('cloud.stats', __name__, url_prefix='/s')
 
@@ -14,20 +14,17 @@ log = logging.getLogger(__name__)
 def get_stats(before: datetime.datetime):
     query_comments = {'node_type': 'comment'}
     query_assets = {'node_type': 'asset'}
-    # TODO Actually query per home project (and 1 blend per project)
-    query_user_blender_sync = {'name': 'startup.blend'}
 
     if before:
         d = {'_created': {'$lt': before}}
         query_comments.update(d)
         query_assets.update(d)
-        query_user_blender_sync.update(d)
 
     stats = {
         'comments': count_nodes(query_comments),
         'assets': count_nodes(query_assets),
         'users_total': count_users(),
-        'users_blender_sync': count_nodes(query_user_blender_sync),
+        'users_blender_sync': count_blender_sync(),
     }
     return stats