[Etherpad] Disable rotation of pad.picasoft.net backups

Revert this commit to enable backups again.

Cf. 21c1e819

pica-db-backup-rotation/config/backup_config.json

@@ -10,17 +10,6 @@
               "Month" : 12
           }
     },
-    "etherpad":
-    {
-      "Folder": "etherpad",
-      "Backup-Rota":
-          {
-              "Hour" : 24,
-              "Day" : 7,
-              "Week" : 4,
-              "Month" : 12
-          }
-    },
     "wekan":
       {
         "Folder": "wekan",