Vcs: Add scrollbar to AddToVcsDialog
Vcs: Add scrollbar to AddToVcsDialog

This makes it handle adding a long list of files more gracefully.

Task-number: QTCREATORBUG-8467
Change-Id: I54dc0e405295694b4ea46ea426397223eb931722
Reviewed-by: Kai Koehne <077bc265216106fb22408e62f2d97925ede69d10@theqtcompany.com>
Reviewed-by: Tobias Hunger <012f8d714267bccc9d4766fbeace9f175fcc70c4@theqtcompany.com>

martyone/sailfish-qtcreator,kuba1/qtcreator,amyvmiwei/qt-creator,danimo/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,farseerri/git_code,xianian/qt-creator,danimo/qt-creator,kuba1/qtcreator,kuba1/qtcreator,Distrotech/qtcreator,AltarBeastiful/qt-creator,danimo/qt-creator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,kuba1/qtcreator,farseerri/git_code,amyvmiwei/qt-creator,danimo/qt-creator,kuba1/qtcreator,amyvmiwei/qt-creator,Distrotech/qtcreator,kuba1/qtcreator,AltarBeastiful/qt-creator,farseerri/git_code,xianian/qt-creator,martyone/sailfish-qtcreator,amyvmiwei/qt-creator,AltarBeastiful/qt-creator,farseerri/git_code,AltarBeastiful/qt-creator,AltarBeastiful/qt-creator,kuba1/qtcreator,kuba1/qtcreator,xianian/qt-creator,Distrotech/qtcreator,AltarBeastiful/qt-creator,kuba1/qtcreator,farseerri/git_code,martyone/sailfish-qtcreator,danimo/qt-creator,farseerri/git_code,Distrotech/qtcreator,martyone/sailfish-qtcreator,farseerri/git_code,danimo/qt-creator,Distrotech/qtcreator,martyone/sailfish-qtcreator,farseerri/git_code,xianian/qt-creator,amyvmiwei/qt-creator,AltarBeastiful/qt-creator,xianian/qt-creator,danimo/qt-creator,Distrotech/qtcreator,amyvmiwei/qt-creator,Distrotech/qtcreator,xianian/qt-creator,danimo/qt-creator,xianian/qt-creator,AltarBeastiful/qt-creator,amyvmiwei/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,danimo/qt-creator