chore: hide docker integration behind the curtain (#17715)

This is not ready for the prime time yet.

docs/src/docker.md

@@ -146,59 +146,3 @@ The image will be tagged as `playwright:localbuild-focal` and could be run as:
 docker run --rm -it playwright:localbuild /bin/bash
 ```
 
-## (Experimental) Playwright Test Docker Integration
-* langs: js
-
-Playwright Test now ships an **experimental** Docker integration. The Docker container provides a consistent environment, eliminating browser rendering differences across platforms. 
-With this integration, **only** browser binaries are running inside a Docker container,
-while all the code is still running on the host operating system.
-
-Playwright Test will automatically proxy host network traffic
-into the container, so browsers can access servers running on the host.
-
-:::note
-Docker integration requires Docker installed & running on your computer.
-See https://docs.docker.com/get-docker/
-
-If you use [Docker Desktop](https://www.docker.com/products/docker-desktop/), make sure to increase
-default CPU and memory limit for better performance.
-:::
-
-Docker integration usage:
-
-1. Build a local Docker image that will be used to run containers. This step
-   needs to be done only once.
-
-    ```bash js
-    npx playwright docker build
-    ```
-
-1. Run Docker container in the background.
-
-    ```bash js
-    npx playwright docker start
-    ```
-
-1. Run tests inside Docker container using the `PLAYWRIGHT_DOCKER` environment variable.
-   You can set this environment variable as a part of your config:
-
-    ```ts
-    // playwright.config.ts
-    import type { PlaywrightTestConfig } from '@playwright/test';
-
-    process.env.PLAYWRIGHT_DOCKER = '1';
-
-    const config: PlaywrightTestConfig = {
-      /* ... configuration ... */
-    };
-    export default config;
-    ```
-
-   NOTE: Playwright will automatically detect a running Docker container or start it if needed.
-
-1. Finally, stop background Docker container when you're done working with tests:
-
-    ```bash js
-    npx playwright docker stop
-    ```
-

packages/playwright-core/src/containers/docker.ts

@@ -276,7 +276,7 @@ function createStacklessError(message: string) {
 }
 
 export function addDockerCLI(program: Command) {
-  const dockerCommand = program.command('docker')
+  const dockerCommand = program.command('docker', { hidden: true })
       .description(`Manage Docker integration (EXPERIMENTAL)`);
 
   dockerCommand.command('build')