Fix typescript errors

[jakobkolb]

Currently, there are 1980 typescript errors in the front end code base. We want to fix them, so we properly use linting and typechecking in the future.

[jakobkolb]

As of b72651c there are still:

typescript errors	action
1833	initially
680	after setting "noImplicitAny": false
806	after installing all the missing types

So it seems, there is no easy fix for this. Will default to @ts-ignoreing all the existing type errors, so we can at least get some feedback on our own work.