(style): add service and preference to switch from one theme to another.
Description
Implement a service to switch from one theme (style) to another, and save the last one in the preferences.
Proposal
// Parse all the *.qss
QString path("/home/mschweitzer/dev/Sight/build/debug/share/sight/style-0.1/flatdark.qss");
QFile data(path);
QString style;
if(data.open(QFile::ReadOnly))
{
QTextStream styleIn(&data);
style = styleIn.readAll();
data.close();
}
// Switch from one style to another
qApp->setStyleSheet(style);
Links / references
Linked to #436 (closed), since we haven't any light theme.