adds umbra logo and token data (#341)

Author: R-K-H

scripts/assets/UMBRA/UMBRA.json

@@ -0,0 +1,6 @@
+{
+  "name": "Umbra",
+  "symbol": "UMBRA",
+  "description": "Umbra Privacy is a Solana-based protocol designed to enable private transactions onchain. Umbra powers private swaps, transfer and enables dApps to integrate privacy directly into their user experience.",
+  "image": "https://raw.githubusercontent.com/metaDAOproject/futarchy/refs/heads/develop/scripts/assets/UMBRA/UMBRA.png"
+}