misc-changes: Save state

- Header handling fixes
- IPRO Flow fixes
- Make request context persist throughout the request lifetime in
  a hacky way to prevent double work and simplify (or don't backstab)
  when internal redirects and named locations are involved.
- General fix, don't call base_fetch->Done(false) to prevent unwanted
  events
- I suspect that in case of internal redirects (/ -> index.html) PSOL
  would be misinformed, and operate assuming the rewritten url. This
  fixes that (need to confirm if this originally was a problem).