Move production build tutorials from vaadin/flow-maven-plugin repo to flow/documentation

[pleku]

The topic should be Taking your app into production.

The basis is the https://github.com/vaadin/flow-maven-plugin/blob/master/README.md and it could be starting with describing the steps you need to take the app to the production.

Acceptance Criteria

• There is a tutorial/documentation in Flow that describes what I need to do the get the app ready for production
• The tutorial starts of by answering Why I need to do this, e.g. transpilation and bundling.
• The maven plugin readme links to this tutorial