Revise Manual Routing docs

[rigor789]

Most apps are written with webpack and .vue files by default. In the docs we're writing js only components.

We should revise the docs and update them to include up-to-date examples with .vue files and how that might look/work in an actual app.

We're also showing an example of navigating in an inline event handler @tap="$navigateTo(detailPage)" which requires adding detailPage to data. This is not a recommended approach, as this forces vue to mark the component descriptor as reactive. Instead we should focus on making sure that the component that we want to navigate to is imported, and the call to $navigateTo is made inside an event handler method.

I would propose we change the title from Manual Routing to just Navigation