Issue #2702609 by Wim Leers, Berdir, Fabianx: Disable placeholdering (and BigPipe) on unsafe requests to help find forms as fast as possible (to allow EnforcedResponses to work)

Issue #2665992 by alexpott, klausi, heykarthikwithu, xjm, tstoeckler: @file is not required for classes, interfaces and traits

Issue #2469431 by Wim Leers, Fabianx, swentel, nod_, yched, dawehner, tstoeckler, catch, borisson_: BigPipe for auth users: first send+render the cheap parts of the page, then the expensive parts