[qmf] Update to upstream version 4.0.2.
Squashed 'qmf/' changes from 696f60b..95c51a3

95c51a3 Introduce messageserver plugins.

git-subtree-dir: qmf
git-subtree-split: 95c51a3e3e8b23d7d4917ea1a35db16785525aeb
Merge commit '193e319795fec048f0cb0e06e2f7bd62fee20c72'