Update arf.json

oxt.me (Open Explorer Tool) is a basic free chain analysis tool that has many features beneficial to the OSINT community that are not available on most public block explorers.

These features include:
 - User annotations of financial entities, available with a free account (no email required)
 - A conservative wallet clustering algorithm for grouping multiple addresses
 - A transaction graph which is accessible from tool bar on the left side of the transactions tab

public/arf.json

@@ -5548,6 +5548,11 @@
     "children": [
     {
       "children": [
+      {
+        "name": "OXT",
+        "type": "url",
+        "url": "https://oxt.me"
+      },
       {
         "name": "Blocktrail",
         "type": "url",