Another baseurl related fix

[Bond-009]

Baseurl always starts with a '/' (unless it's empty)

Fixes the error from #2380 (Don't know if it fixes the issue)

[JustAMan]

I'm not sure it's correct, I'd rather see us normalizing a URL before processing it... because //jellyfin should be identical to /jellyfin IMHO

[Bond-009]

What do you mean? We know for a fact the baseurl start with a '/' we make sure of that in the setter of the property

[JustAMan]

@Bond-009 okay, here's your greenmark from me.
But still, normalizing a URL prior to processing it sounds a right thing to do... though it's probably should be done by Kestrel, not us.

[Bond-009]

We don't process any url here, we take the hostname and create a url from that