[Releasing] rename qtwebkit-examples-and-demos => qtwebkit-examples?

[Oswald Buddenhagen]

moin,

for sanity and accuracy, i'd like to rename this repo.
the impact is rather small:
- repo rename: minor disruption, but as almost nobody is working on it,
  most people won't notice anything beyond a (very small) module
  appearing and another disappearing
- adjust qt5.git (.gitmodules, qt.pro, init-repository)
- packaging
  - upstream: this will have no noticable impact except the name in the
    installer lists
  - downstream: as the repo is logically part of qtwebkit, i would not
    expect it to be separately packaged in the first place, but follow
    the packaging scheme of the examples of other qt modules

unless there is substantial resistance, i'll do that in a few weeks
(after 5.0.2 is out and it is clear that 5.0.3 won't happen on regular
schedule (or it did actually happen)).