Align everything to Node.js 16 (#22223)

* Update nvmrc to Node.js 16

* Update package.json minimum Node engine to 16

* Update README requirements to Node.js 16

* Update devcontainer Node.js version to 16

* Update devcontainer Dockerfile Node.js choices to LTS versions that are still in support/maintenance

* Pin CircleCI Node image to 16

* Fix YAML type issue

* Update CircleCI Node.js to 16.18 to match #22019