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>

relay.config.json

@@ -0,0 +1,50 @@
+{
+  "root": ".",
+  "sources": {
+    "apps/console/src/pages/iam": "iam",
+    "apps/console/src": "core",
+    "apps/trust/src": "trust"
+  },
+  "projects": {
+    "core": {
+      "schema": "pkg/server/api/console/v1/schema.graphql",
+      "language": "typescript",
+      "noFutureProofEnums": true,
+      "output": "apps/console/src/__generated__/core",
+      "relativizeJsModulePaths": false,
+      "customScalarTypes": {
+        "Datetime": "string",
+        "GID": "string",
+        "CursorKey": "string",
+        "Duration": "string",
+        "BigInt": "number",
+        "EmailAddr": "string"
+      }
+    },
+    "iam": {
+      "schema": "pkg/server/api/connect/v1/schema.graphql",
+      "language": "typescript",
+      "noFutureProofEnums": true,
+      "output": "apps/console/src/__generated__/iam",
+      "relativizeJsModulePaths": false,
+      "customScalarTypes": {
+        "Datetime": "string",
+        "GID": "string",
+        "CursorKey": "string",
+        "Duration": "string",
+        "BigInt": "number",
+        "EmailAddr": "string"
+      }
+    },
+    "trust": {
+      "schema": "pkg/server/api/trust/v1/schema.graphql",
+      "language": "typescript",
+      "noFutureProofEnums": true,
+      "customScalarTypes": {
+        "Datetime": "string",
+        "CursorKey": "string",
+        "EmailAddr": "string"
+      }
+    }
+  }
+}