qmake: support incremental linking when embedding manifests

qmake: support incremental linking when embedding manifests

When embedding manifests we modified the EXE/DLL after linking using
the manifest tool. This breaks the incremental linking feature of MSVC.

The MS way to embed a manifest without breaking incremental linking is:
   - let the linker create the manifest file,
   - create a resource that contains the manifest file,
   - invoke the linker again to embed the resource.

The embed_manifest_{exe|dll}.prf files have been removed.
All manifest logic is now in qmake's nmake makefile generator.

With QMAKE_MANIFEST one can specify a custom manifest file that gets
embedded without disturbing incremental linking.

Task-number: QTBUG-22718
Change-Id: Idb9d2644a0577b2002cbdd2d62b695b9171b1bd5
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@nokia.com>