tokens: Add Bitcoin token list.

token/bitcoin_token_list.json

@@ -0,0 +1,12 @@
+{
+  "name": "Bitcoin Token List",
+  "tokens": [
+    {
+      "chainId": 1,
+      "address": "1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa",
+      "symbol": "BTC",
+      "name": "Bitcoin",
+      "decimals": 8
+    }
+  ]
+}