Use headless Chromium instead of PhantomJS

• #477 Chrome-headless - DNS and Connect timings (by @gnublin)
• #618 Chrome-headless - New metric proposal "synchronousXHR" (by @gmetais)
• #620 bug - Timeout caused by synchronous XMLHttpRequests (by @gmetais)
• #707 Chrome-headless - Switch from PhantomJS to Chrome's headless mode
• #726 Chrome-headless - Refactor Phantomas to run using headless Chrome
• #728 documentation - Move metrics description to docs/metrics.md and generate it automatically
• #729 documentation - Automatically generate events documentation
• #730 documentation - Add events, extensions and modules to metadata JSON file
• #732 Chrome-headless - windowPerformance in headless Chrome (by @sundarv85)
• #734 pr - New metric proposal "synchronousXHR"
• #736 internals - Update dependencies
• #741 Chrome-headless - Prepare a Docker image with Puppeteer installed
• #742 Chrome-headless - Puppeteer v1.15.0
• #743 enhancement - Upgrade js-yaml to resolve security issues
• #744 Chrome-headless - Puppeteer in docker
• #747 external dependency - build(deps): bump eslint-utils from 1.3.1 to 1.4.3 (by @dependabot[bot])
• #748 external dependency - build(deps): bump lodash from 4.17.11 to 4.17.15 (by @dependabot[bot])
• #749 bug - Failed to parse JSON with the results (by @jatin85)
• #750 external dependency - build(deps): bump acorn from 6.1.0 to 6.4.1 (by @dependabot[bot])
• #751 external dependency - build(deps): bump https-proxy-agent from 2.2.1 to 2.2.4 (by @dependabot[bot])
• #752 external dependency - build(deps): bump lodash from 4.17.15 to 4.17.19 (by @dependabot[bot])
• #753 pr - Phantomas V2 - the final merge into the main branch
• #754 external dependency - build(deps): bump async from 2.6.3 to 3.2.0 (by @dependabot[bot])
• #755 external dependency - build(deps): bump csv-string from 3.2.0 to 4.0.1 (by @dependabot[bot])
• #756 external dependency - build(deps-dev): bump eslint from 7.5.0 to 7.6.0 (by @dependabot[bot])
• #757 pr - Run tests using Node.js 12.x too
• #758 pr - Use http-server for tests (fixes qs security issue)
• #759 pr - Browser.close - check if there is a browser to call close() on
• #760 external dependency - build(deps): bump analyze-css from 0.12.10 to 0.12.11 (by @dependabot[bot])
• #761 security - Use commander module
• #762 pr - Make npm package a bit smaller
• #763 pr - Fix bin/phantomas.js
• #764 Chrome-headless - [Phantomas v2] Navigation failed because browser has disconnected! (by @gmetais)
• #766 external dependency - build(deps-dev): bump js-beautify from 1.11.0 to 1.12.0 (by @dependabot[bot])
• #767 external dependency - build(deps-dev): bump eslint from 7.6.0 to 7.7.0 (by @dependabot[bot])
• #768 external dependency - build(deps-dev): bump js-beautify from 1.12.0 to 1.13.0 (by @dependabot[bot])
• #769 Chrome-headless - Node.js 14.x integration tests are failing on response size asserts
• #771 enhancement - Add WOFF2 detection (by @gmetais)
• #772 external dependency - build(deps-dev): bump eslint from 7.7.0 to 7.8.0 (by @dependabot[bot])
• #773 docker - Use nginx to make integration tests more deterministic
• #774 external dependency - build(deps-dev): bump eslint from 7.8.0 to 7.8.1 (by @dependabot[bot])
• #777 internals - Improve tests with shorter expire policy + no gzip
• #778 external dependency - build(deps): bump analyze-css from 0.12.11 to 0.12.12 (by @dependabot[bot])
• #779 external dependency - build(deps-dev): bump eslint from 7.8.1 to 7.9.0 (by @dependabot[bot])
• #780 external dependency - build(deps): bump puppeteer from 5.2.1 to 5.3.0 (by @dependabot[bot])
• #781 external dependency - build(deps): bump debug from 4.1.1 to 4.2.0 (by @dependabot[bot])
• #782 external dependency - build(deps): bump puppeteer from 5.3.0 to 5.3.1 (by @dependabot[bot])
• #783 external dependency - build(deps-dev): bump eslint from 7.9.0 to 7.10.0 (by @dependabot[bot])
• #784 Chrome-headless - Add support for viewport option (by @gmetais)
• #786 internals - Tests: use the latest macbre/nginx-brotli - 1.19.3
• #787 bug - Adjustments to lazyloadable images (by @gmetais)
• #788 pr - waitFor is now deprecated
• #789 internals - Dockerfile - use node:14-stretch-slim base image
• #791 internals - Introduce Prettier
• #792 bug - [Phantomas v2] Scope seems to be initialized twice (by @gmetais)
• #793 internals - core/scope.js: log window URL and whether it is an iframe
• #794 external dependency - build(deps-dev): bump eslint from 7.10.0 to 7.11.0 (by @dependabot[bot])
• #796 external dependency - build(deps-dev): bump eslint-config-prettier from 6.12.0 to 6.13.0 (by @dependabot[bot])
• #797 docker - Try to use Alpine as a base Docker image
• #798 pr - Docker - use alpine3.12 base image
• #799 external dependency - build(deps-dev): bump eslint-config-prettier from 6.13.0 to 6.14.0 (by @dependabot[bot])
• #800 docker - Fixing "No usable sandbox" when running inside Docker container
• #802 cli - bin/phantomas.js should output Browser.visit() promise rejections to stderr
• #803 internals - Update CI build names
• #808 internals - Makes tests crash on unhandled rejections instead of silently ignoring them