separating state variables regarding server/request

separating state variables regarding server/request

Having a Reset(bool) method to partially reset certain variables like
the download size always were strange, so this commit splits the
ServerState into an additional RequestState living on the stack for as
long as we deal with this request causing an automatic "reset".

There is much to do still to make this code look better, but this is a
good first step which compiles cleanly and passes all tests, so keeping
it as history might be beneficial and due to avoiding explicit memory
allocations it ends up fixing a small memory leak in https, too.

Closes: #440057