docs: fixed no images in docs when build out of source
docs: fixed no images in docs when build out of source

JoshuaKolden/qca,JoshuaKolden/qca,oktavarium/qca,Bjoe/qca,KDE/qca,Bjoe/qca,karolherbst/qca,KDE/qca,KDE/qca,KDE/qca,oktavarium/qca,karolherbst/qca,Bjoe/qca,karolherbst/qca,JoshuaKolden/qca,oktavarium/qca,oktavarium/qca,karolherbst/qca,JoshuaKolden/qca,Bjoe/qca