Upgrade Relay to v20.1.1 and unify compiler config

Consolidate the two per-app relay configs (console and trust)
into a single multi-project relay.config.json at the repo root
with three projects: core, iam, and trust. Bump all relay
packages from v19 to v20.1.1 and move relay-compiler to the
root devDependencies. Replace per-workspace relay scripts with
a single root-level npm run relay command and update the
GNUmakefile, CI workflows, and docs accordingly.

Signed-off-by: Émile Ré <emile@getprobo.com>

.github/workflows/release.yaml

@@ -24,14 +24,13 @@ jobs:
         with:
           go: "false"
       - run: "npm --workspace @probo/emails run build"
+      - run: "npm run relay"
       - name: "Build console"
         run: |
-          npm --workspace @probo/console run relay
           npm --workspace @probo/console run check
           NODE_ENV=production npm --workspace @probo/console run build
       - name: "Build trust"
         run: |
-          npm --workspace @probo/trust run relay
           npm --workspace @probo/trust run check
           NODE_ENV=production npm --workspace @probo/trust run build
       - uses: "actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f" # v7