Hi Andre,
I have the same task to solve and have not a perfect solution.
I'am using this code now in drawerView.js (after line17)
if(Adapt.config.get('_drawer')._drawerPosition=='left'){
this.drawerDir = 'left';
//adding class to move drawer-icon to the left
$('#adapt').addClass('drawer-left');
}
new attribute _drawerPosition for _drawer in config.json
"_drawer": {
"_showEasing": "easeOutQuart",
"_hideEasing": "easeInQuart",
"_duration": 400,
"_drawerPosition":"left"
}
and in LESS
.drawer-left .navigation .navigation-drawer-toggle-button{
float: left;
}
but of course you need to be carefull with updates and its not the solution for Authoring Tool.
Maybe someone has a better way to do this? Like overwrite DrawerView initialize function with theme or plugin would be nice - and not only in this case.