Consider allowing `ExportData.filename_reverse = True` through forward models

Some user feedback:

> Some assets calculate 4D differences by subtracting base – monitor_survey, in contrast to the normal monitor – base, and name the cubes, maps, etc. alike.
>
> In fmu-dataio you can set `ExportData.filename_reverse = True` and the filenames and metadata are exported with base_monitor order.
>
> However, when you run the ERT forward models `GRID3D_AVERAGE_MAP` and `GRID3D_HC_THICKNESS`, you don’t have this option, at least as far as I know.
> My workaround is a custom ERT forward model, basically a python script, that renames all the 4D map files and rewrites the metadata files with updated filename references and t0 and t1 dates.

We could consider offering this option through the forward model. It has a rather niche use case, but it is probably preferred over user scripts rewriting metadata.