Don't advertise qmlviewer as a 'deployment solution' in qmlruntime.html

doc/src/declarative/qmlruntime.qdoc right now advertises qmlviewer as a way to 'deploy a QML application'. However, we finally decided that qmlviewer shouldn't be more than a development/debugging tool, and that deployment to users devices should always use a custom main.cpp wrapper. We plan also to support this in QtCreator.

qmlruntime.qdoc should be rewritten to reflect this - maybe the sections describing qmlviewer even deserve their own page.