Make pageProps typesafe

[FleetAdmiralJakob]

Goals

1. No anys in the pageProps

Non-Goals

1. Make the pages router in general more typesafe

Background

As able to see here, the pageProps from the AppProps are typed as any which is not really recommended. I now have to suppress this ESLint rule for this line.

Proposal

Type the AppProps properly

PS: Sorry for the light mode