Enable to merge separate geometries into single mesh at export time (procedural models)

[_Olivier_L]

Procedural models can generate meshes with geometries disconnected from each other. When exporting the object, Stager exports each separate geometry as a separate mesh. Please provide an option to export as a single mesh.

[Methelde]

This is much needed!

[Ares Hovhannesyan]

IMHO for that we need boleen operation.