Steps of wizard should be navigatable via back/forward button of the browser?

[LukasKalbertodt]

I find myself regularly accidentally pressing the brower's back button to go back a step in the wizard only to find myself on a completely different page. So I think we should make the wizard work with those buttons. However, there are a few gotchas:

• We can't just listen for back/forward events. We instead have to use the history API and have a different URL for each step (i.e. /video-select, ...)
• If we use the current router with real paths (e.g. /video-select), then the problem of redirecting those requests to the SPA get more prominent. We already have the problem of redirecting /settings and /about. It works for GitHub pages, but people deploying themselves and the version integrated into Opencast have that problem.
• When implementing this, we again need to make sure that the user can't accidentally throw away a recording.