renovate(host): set up Renovate using role and exisiting config

Set up Renovate using role and existing config from current
Forgejo/GitHub Actions-based deployment.

resources/chaosknoten/renovate/renovate/config.js.j2

@@ -0,0 +1,22 @@
+module.exports = {
+    username: "renovate",
+    token: "{{ secret__renovate_token }}",
+    endpoint: "https://git.hamburg.ccc.de/",
+    platform: "gitea",
+    persistRepoData: true,
+    logLevel: "debug",
+    onboardingConfig: {
+        "extends": ["config:recommended"],
+    },
+    autodiscover: true,
+    autodiscoverNamespaces: [
+        "CCCHH"
+    ],
+    detectHostRulesFromEnv: false,
+    hostRules: [
+        {
+            matchHost: "api.github.com",
+            token: "{{ secret__renovate_github_token }}"
+        }
+    ]
+};