LitElement tutorial part 4: Navigation and code splitting

Text version and code: https://vaadin.com/tutorials/lit-element/navigation-and-code-splitting *Note: the npm package name and import path for lit-element has changed from @polymer/lit-element to just lit-element. Check the text version for up to date code snippets* In this tutorial, you'll learn how to navigate between views in a LitElement application and how to split code based on routes. Previous video: https://youtu.be/_Gt12UhGLY0 Next video: https://youtu.be/ToxKlmqgZHw