Root signing page and a root chain check for replacing the root keys (#81)

- signed_config.py root drafts a later root in docs/root-signing/proposals/,
  where wallets never look, and keeps the current targets key by default.
- docs/root-signing/: a page for the Pezkuwi Wallet DApp browser that shows
  the proposal and its fingerprint, has the holder's wallet sign
  <Bytes>payload</Bytes>, checks every signature as the wallet will, collects
  signature codes and offers root.N.json once two current and two new holders
  have signed. Crypto bundles are served beside it.
- scripts/root/verify_root.mjs checks every published signed/root.N.json the
  way installed wallets do; Code Quality runs it. Wallet 1.3.0 accepts sr25519
  only under the substrate signing context, and a root it cannot verify stops
  its config refresh, so such a root must never reach master.
- Draft root 2: three new holder accounts, threshold 2, five years.

scripts/root/package.json

@@ -0,0 +1,12 @@
+{
+  "name": "pezkuwi-wallet-utils-root",
+  "private": true,
+  "type": "module",
+  "description": "Verifies the signed config root chain as the wallet does",
+  "dependencies": {
+    "@pezkuwi/util": "14.0.26",
+    "@pezkuwi/util-crypto": "14.0.26",
+    "@polkadot/util": "13.5.9",
+    "@polkadot/util-crypto": "13.5.9"
+  }
+}