chore: create Gitpod configuration (#12210)

.gitpod.yml

+tasks:
+  - init: >
+      nvm install 16 &&
+      nvm use 16 &&
+      yarn install &&
+      yarn run build
+    command: yarn run start

docs/development/remote-development.md

+# Remote Development
+
+This document gives tips and tricks on how to run Renovate in a remote container to add features or fix bugs.
+You can improve this documentation by opening a pull request.
+For example, if you think anything is unclear, or you think something needs to be added, open a pull request!
+
+## First read the local development docs
+
+Read the [local development docs](./local-development.md) first.
+
+## What's remote development?
+
+When you work locally, you install the tooling and code editor on your computer.
+You are responsible for setting up the environment correctly.
+
+With remote development you use a container that's hosted somewhere else.
+You'll use the same code editor and have the same config as all other developers.
+
+### Benefits
+
+- You only need a browser and internet
+- You don't need to install development dependencies on your computer
+- Start work in a fresh environment every time
+- Reproducible development environment
+- Similar config for all developers
+- Use VSCode in the browser
+
+### Drawbacks
+
+- Waiting for the remote container to start
+- If your internet is down or Gitpod or GitHub Codespaces are down then you can't work
+
+## Gitpod
+
+You can use [Gitpod](https://gitpod.io/) for light development work like:
+
+- Editing the docs
+- Running ESLint, Prettier
+
+For proper development, use GitHub Codespaces.
+
+The config file for Gitpod is `.gitpod.yml` in the root of the repository.
+
+Gitpod comes with 50 free hours each month.
+If you need more hours you'll need to buy a plan with more hours.
+
+### Gitpod tips
+
+- Use `yarn jest:16` to run the tests on Gitpod
+
+### Known problems with Gitpod
+
+- `yarn jest:16` has some failing tests
+- You can't preview Markdown files in the VS Code online editor
+
+## GitHub Codespaces
+
+The Renovate developers use [GitHub Codespaces](https://github.com/features/codespaces).
+The config files are in the `.devcontainer` folder in the repository.
+
+You can only use GitHub Codespaces if you're invited into the beta by GitHub.