Migrate react-router from v5 to v6

[leventebalogh]

Why?

Grafana core allows plugins to start using the v6 version of react-router, and hopefully we will deprecate using v5 in plugins this year. @grafana/scenes is used by internal app plugins, which means that before migrating those we need to have a version of the scenes package that supports versions 6.x.x as well.

How?

For the scenes-app follow our migration guide using create-plugin, and for scenes rely on the official react-router v5->v6 migration guide.

Some of the things that need too be changed: (list is not complete)

• [ ] SceneApp: Use <Routes> instead of <Switch>
• [ ] SceneApp: Stop using the render={} prop in Route components, use the element={} prop instead and the useParams() hook
• [ ] SceneAppPage: stop using the render={} prop and the <Switch> component
• [ ] Routes: stop using the <Switch> component