Remove dead link and empty folder: ThatsThem VIN Search, Base64

- Remove That's Them VIN Search (thatsthem.com/vin-search) - reported
  dead in GH #490; the VIN search feature was removed by the site owner
- Remove empty Base64 folder (children: []) - caused the folder to
  appear clickable but do nothing, reported in GH #489

Co-Authored-By: Paperclip <noreply@paperclip.ing>

public/arf.json

@@ -3377,11 +3377,6 @@
           "name": "Vehicle Records",
           "type": "folder",
           "children": [
-            {
-              "name": "That's Them VIN Search",
-              "type": "url",
-              "url": "https://thatsthem.com/vin-search"
-            },
             {
               "name": "MyAccident - traffic accident map",
               "type": "url",
@@ -5028,11 +5023,6 @@
       "name": "Encoding / Decoding",
       "type": "folder",
       "children": [
-        {
-          "name": "Base64",
-          "type": "folder",
-          "children": []
-        },
         {
           "name": "Barcodes / QR",
           "type": "folder",