Adding step to build the app with docker in existing projects (#34083)
* Adding steps to build the app with docker in existing projects (without the need to create the app with the with-docker example)
* Update examples/with-docker/README.md
Fix uppercase
Co-authored-by: Balázs Orbán <info@balazsorban.com>
* lint-fix
Co-authored-by: JJ Kasper <jj@jjsweb.site>