Doc: add the link to install QtWebKit
Doc: add the link to install QtWebKit

Rewrote the introduction.

Task-number: QTSDK-587

Reviewed-by: Jerome Pasion
(cherry picked from commit b9614cdf7d6b09d0c1723e6a3534ca3991cd8a4b)

renatofilho/QtCreator,syntheticpp/qt-creator,Distrotech/qtcreator,azat/qtcreator,syntheticpp/qt-creator,renatofilho/QtCreator,hdweiss/qt-creator-visualizer,darksylinc/qt-creator,danimo/qt-creator,KDE/android-qt-creator,syntheticpp/qt-creator,kuba1/qtcreator,syntheticpp/qt-creator,colede/qtcreator,bakaiadam/collaborative_qt_creator,martyone/sailfish-qtcreator,KDAB/KDAB-Creator,dmik/qt-creator-os2,farseerri/git_code,KDE/android-qt-creator,darksylinc/qt-creator,jonnor/qt-creator,KDE/android-qt-creator,syntheticpp/qt-creator,malikcjm/qtcreator,renatofilho/QtCreator,maui-packages/qt-creator,Distrotech/qtcreator,richardmg/qtcreator,amyvmiwei/qt-creator,hdweiss/qt-creator-visualizer,malikcjm/qtcreator,xianian/qt-creator,darksylinc/qt-creator,kuba1/qtcreator,darksylinc/qt-creator,Distrotech/qtcreator,Distrotech/qtcreator,renatofilho/QtCreator,omniacreator/qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,AltarBeastiful/qt-creator,azat/qtcreator,jonnor/qt-creator,KDE/android-qt-creator,pcacjr/qt-creator,malikcjm/qtcreator,maui-packages/qt-creator,danimo/qt-creator,danimo/qt-creator,KDAB/KDAB-Creator,hdweiss/qt-creator-visualizer,colede/qtcreator,jonnor/qt-creator,renatofilho/QtCreator,danimo/qt-creator,martyone/sailfish-qtcreator,richardmg/qtcreator,jonnor/qt-creator,bakaiadam/collaborative_qt_creator,martyone/sailfish-qtcreator,azat/qtcreator,danimo/qt-creator,KDAB/KDAB-Creator,kuba1/qtcreator,pcacjr/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,omniacreator/qtcreator,ostash/qt-creator-i18n-uk,Distrotech/qtcreator,ostash/qt-creator-i18n-uk,richardmg/qtcreator,pcacjr/qt-creator,amyvmiwei/qt-creator,kuba1/qtcreator,farseerri/git_code,omniacreator/qtcreator,KDE/android-qt-creator,syntheticpp/qt-creator,AltarBeastiful/qt-creator,duythanhphan/qt-creator,hdweiss/qt-creator-visualizer,martyone/sailfish-qtcreator,colede/qtcreator,AltarBeastiful/qt-creator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,KDAB/KDAB-Creator,duythanhphan/qt-creator,kuba1/qtcreator,amyvmiwei/qt-creator,danimo/qt-creator,azat/qtcreator,colede/qtcreator,maui-packages/qt-creator,ostash/qt-creator-i18n-uk,bakaiadam/collaborative_qt_creator,pcacjr/qt-creator,kuba1/qtcreator,amyvmiwei/qt-creator,richardmg/qtcreator,colede/qtcreator,danimo/qt-creator,darksylinc/qt-creator,AltarBeastiful/qt-creator,ostash/qt-creator-i18n-uk,amyvmiwei/qt-creator,kuba1/qtcreator,farseerri/git_code,dmik/qt-creator-os2,maui-packages/qt-creator,KDAB/KDAB-Creator,danimo/qt-creator,KDE/android-qt-creator,hdweiss/qt-creator-visualizer,colede/qtcreator,richardmg/qtcreator,duythanhphan/qt-creator,kuba1/qtcreator,xianian/qt-creator,colede/qtcreator,ostash/qt-creator-i18n-uk,farseerri/git_code,richardmg/qtcreator,martyone/sailfish-qtcreator,AltarBeastiful/qt-creator,bakaiadam/collaborative_qt_creator,malikcjm/qtcreator,duythanhphan/qt-creator,AltarBeastiful/qt-creator,AltarBeastiful/qt-creator,darksylinc/qt-creator,omniacreator/qtcreator,maui-packages/qt-creator,farseerri/git_code,dmik/qt-creator-os2,jonnor/qt-creator,dmik/qt-creator-os2,jonnor/qt-creator,maui-packages/qt-creator,kuba1/qtcreator,KDE/android-qt-creator,hdweiss/qt-creator-visualizer,amyvmiwei/qt-creator,KDAB/KDAB-Creator,bakaiadam/collaborative_qt_creator,xianian/qt-creator,pcacjr/qt-creator,danimo/qt-creator,ostash/qt-creator-i18n-uk,xianian/qt-creator,azat/qtcreator,azat/qtcreator,bakaiadam/collaborative_qt_creator,farseerri/git_code,Distrotech/qtcreator,malikcjm/qtcreator,Distrotech/qtcreator,syntheticpp/qt-creator,xianian/qt-creator,malikcjm/qtcreator,AltarBeastiful/qt-creator,darksylinc/qt-creator,omniacreator/qtcreator,maui-packages/qt-creator,duythanhphan/qt-creator,dmik/qt-creator-os2,bakaiadam/collaborative_qt_creator,KDE/android-qt-creator,renatofilho/QtCreator,richardmg/qtcreator,darksylinc/qt-creator,dmik/qt-creator-os2,xianian/qt-creator,omniacreator/qtcreator,malikcjm/qtcreator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,pcacjr/qt-creator,pcacjr/qt-creator,farseerri/git_code,duythanhphan/qt-creator,farseerri/git_code,omniacreator/qtcreator,ostash/qt-creator-i18n-uk,duythanhphan/qt-creator,dmik/qt-creator-os2