feat: add Docker image for the MCP server

[MukundaKatta]

Summary

• add a multi-stage Dockerfile for building and running chrome-devtools-mcp
• install Google Chrome in the runtime image and start the server in headless mode by default
• document the container workflow in the README and exclude unnecessary files from build context

Testing

• npm ci
• npm run build
• node build/src/bin/chrome-devtools-mcp.js --help

Closes #584

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.