keycloak, grafana: their public names come from the mesh, not the manifest

GF_SERVER_ROOT_URL=https://grafana.zurag.be, KC_HOSTNAME=https://keycloak.novox.be
and the served issuer's novox default were domains in definitions — wrong on
every other machine (ADR 0112). The names now come from ${bound:route:name}
(mesh-controller #149, hq 122): grafana's in oidc.env, keycloak's in a
hostname.env its server reads. The issuer includes the realm and stays the
assignment's, with no default: unset, a consumer asking for it is refused
and the provisioner says so, rather than both quietly using novox's URL.

Rendered through mesh-controller #149 from these manifests on a zurag.be
node: KC_HOSTNAME=https://keycloak.zurag.be, GF_SERVER_ROOT_URL=
https://grafana.zurag.be, OIDC URLs from the issuer setting. Needs #149
merged and rolled out first.

modules/keycloak/module.json

@@ -49,7 +49,6 @@
   ],
   "serves": {
     "oidc-client": {
-      "issuer": "https://keycloak.novox.be/realms/master",
       "authorization-path": "/protocol/openid-connect/auth",
       "token-path": "/protocol/openid-connect/token",
       "userinfo-path": "/protocol/openid-connect/userinfo"
@@ -103,6 +102,13 @@
       "type": "network",
       "name": "keycloak"
     },
+    {
+      "id": "hostname",
+      "type": "file",
+      "path": "/var/lib/keycloak/hostname.env",
+      "mode": "0644",
+      "content": "KC_HOSTNAME=https://${bound:route:name}\n"
+    },
     {
       "id": "server",
       "type": "container",
@@ -116,24 +122,27 @@
         "KC_DB": "postgres",
         "KC_HTTP_ENABLED": "true",
         "KC_HEALTH_ENABLED": "true",
-        "KC_HOSTNAME": "https://keycloak.novox.be",
         "KC_PROXY_HEADERS": "xforwarded"
       },
       "env-file": [
         "/var/lib/keycloak/admin.env",
-        "/var/lib/keycloak/database.env"
+        "/var/lib/keycloak/database.env",
+        "/var/lib/keycloak/hostname.env"
       ],
       "ports": [
         "8080"
       ],
-      "secrets-in-environment": "KC_DB_PASSWORD is convertible through a generated keycloak.conf (db-password=); KEYCLOAK_ADMIN_PASSWORD is env-only before Keycloak 26; not yet converted"
+      "secrets-in-environment": "KC_DB_PASSWORD is convertible through a generated keycloak.conf (db-password=); KEYCLOAK_ADMIN_PASSWORD is env-only before Keycloak 26; not yet converted",
+      "restart-on": [
+        "hostname"
+      ]
     },
     {
       "id": "runtime-config",
       "type": "file",
       "path": "/var/lib/mesh/keycloak/config.json",
       "mode": "0600",
-      "content": "{\n  \"issuer\": \"https://keycloak.novox.be/realms/master\"\n}\n",
+      "content": "{}\n",
       "merge": "json"
     },
     {