docs: move docs index/homepage file to main repo (#28751)

Co-authored-by: Michael Kriese <michael.kriese@visualon.de>

docs/usage/index.md

@@ -0,0 +1,91 @@
+![Renovate banner](https://app.renovatebot.com/images/whitesource_renovate_660_220.jpg){ loading=lazy }
+
+# Renovate documentation
+
+Automated dependency updates.
+Multi-platform and multi-language.
+
+## Why use Renovate?
+
+<!-- markdownlint-disable list-marker-space -->
+<!-- prettier-ignore-start -->
+
+<div class="grid cards" markdown>
+
+-   :octicons-git-pull-request-24:{ .lg .middle } __Automatic updates__
+
+    ---
+
+    Get pull requests to update your dependencies and lock files.
+
+-   :octicons-calendar-24:{ .lg .middle } __On your schedule__
+
+    ---
+
+    Reduce noise by scheduling when Renovate creates PRs.
+
+-   :octicons-package-24:{ .lg .middle } __Works out of the box__
+
+    ---
+
+    Renovate finds relevant package files automatically, including in monorepos.
+
+-   :octicons-goal-24:{ .lg .middle } __How you like it__
+
+    ---
+
+    You can customize the bot's behavior with configuration files.
+
+-   :octicons-share-24:{ .lg .middle } __Share your configuration__
+
+    ---
+
+    Share your configuration with ESLint-like config presets.
+
+-   :octicons-sync-24:{ .lg .middle } __Out with the old, in with the new__
+
+    ---
+
+    Get replacement PRs to migrate from a deprecated dependency to the community suggested replacement, works with _most_ managers, see [issue 14149](https://github.com/renovatebot/renovate/issues/14149) for exceptions.
+
+-   :octicons-tools-24:{ .lg .middle } __Open source__
+
+    ---
+
+    Renovate is licensed under the [GNU Affero General Public License](https://github.com/renovatebot/renovate/blob/main/license).
+
+</div>
+
+<!-- prettier-ignore-end -->
+<!-- markdownlint-enable list-marker-space -->
+
+## Supported Platforms
+
+Renovate works on these platforms:
+
+- [GitHub (.com and Enterprise Server)](./modules/platform/github/index.md)
+- [GitLab (.com and CE/EE)](./modules/platform/gitlab/index.md)
+- [Bitbucket Cloud](./modules/platform/bitbucket/index.md)
+- [Bitbucket Server](./modules/platform/bitbucket-server/index.md)
+- [Azure DevOps](./modules/platform/azure/index.md)
+- [AWS CodeCommit](./modules/platform/codecommit/index.md)
+- [Gitea and Forgejo](./modules/platform/gitea/index.md)
+- [Gerrit (experimental)](./modules/platform/gerrit/index.md)
+
+## Who Uses Renovate?
+
+Renovate is used by:
+
+![Renovate Matrix](https://app.renovatebot.com/images/matrix.png){ loading=lazy }
+
+## Ways to run Renovate
+
+You can run Renovate as:
+
+- an [Open Source npm package](https://www.npmjs.com/package/renovate)
+- a [pre-built Open Source image on Docker Hub](https://hub.docker.com/r/renovate/renovate)
+
+Or you can use [the Mend Renovate App](https://github.com/marketplace/renovate) which is hosted by [Mend](https://www.mend.io/).
+
+[Install the Mend Renovate app for GitHub](https://github.com/marketplace/renovate){ .md-button .md-button--primary }
+[Check out our tutorial](https://github.com/renovatebot/tutorial){ .md-button }

tools/docs/test/index.test.mjs

@@ -54,9 +54,6 @@ describe('index', async () => {
     const todo = await glob('**/*.md', { cwd: 'tmp/docs' });
     const files = new Set(todo);
 
-    // Files from https://github.com/renovatebot/renovatebot.github.io/tree/main/src
-    files.add('index.md');
-
     let c = 0;
 
     for (const file of todo) {