Fix network ID and validator icons (#189)

* fix: Validator icons

* fix: Propagation time for blocks < highest

* fix: Reintroduce network_id to Rust backend

packages/frontend/package.json

@@ -21,13 +21,14 @@
   "dependencies": {
     "@fnando/sparkline": "maciejhirsz/sparkline",
     "@types/react-measure": "^2.0.5",
-    "polkadot-identicon": "^1.1.45",
+    "@polkadot/util-crypto": "^1.6.1",
     "react": "16.4.0",
     "react-dom": "16.4.0",
     "react-measure": "^2.3.0",
     "react-scripts-ts": "2.17.0",
     "react-svg": "^4.1.1",
-    "stable": "^0.1.8"
+    "stable": "^0.1.8",
+    "blakejs": "^1.1.0"
   },
   "scripts": {
     "start": "react-scripts-ts start",