ws: Hang onto query string in CockpitWebResponse

So that we can use it in various handlers

Closes #1539
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
base: Fix use of Uint8Array with out the new operator

Get this error message:

  Uncaught TypeError: Constructor Uint8Array requires 'new'

Closes #1542
Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>