Handle temporary layer created by GDAL algorithms

[nicogodet]

In the opposite to QGIS alg native:*, GDAL alg does not create a memory layer as output but instead store a layer in temporary folder (which is deleted at QGIS exit).

It would be nice to handle these layers. How is another question that I don't have the answer yet... (converting them to memory layer at QGIS exit ?)