read.read_cubes should be able to load multiple paths

[jfrost-mo]

What problem does your feature request solve?

When loading multiple models they may be at seperate filesystem locations. It would be nice to load them all in a single read.read_cubes call.

Describe the solution you'd like

Have loadpath also accept a list of pathlikes?

Describe alternatives you've considered

Use lots of wildcarding in the paths. This will work for most things, as we know our file layout, however it doesn't allow us to only select a subset of models or cases.