[ENHANCEMENT] Migrate off of deprecated router

[jcscottiii]

Context: Dependabot opened this PR which bumped vaadin/router to 2.0.1

But it turns out that 2.0.1 was marking the router as deprecated

We should migrate off of it. Their README has the following note:

Consider @lit-labs/router as a more lightweight and modern alternative. Also, as the URLPattern API is universally available in modern browsers nowadays, we recommend using that for building customized client-side routing.

I'm hesitant to moving to lit-labs/router because it seems like it is in the alpha stage