Files served by the ZipVPP are not cached

Steps to reproduce

When files are served by the ZipVPP to the StaticFileHandler they do not get all headers added to give browsers the possibility to cache them.

Steps to repro:

1. Open the Edit UI with a tool to obeserve network traffic enabled (DevTools)

2. Reload the UI with f5/ctrl+r

Observe:

All script/css and so on files are loaded from the server again (response 200)

Expected:

Cache check with server (response 304)