Don't copy forcing for Hype model

[sverhoeven]

At the moment the forcings are copied to the working directory at https://github.com/eWaterCycle/ewatercycle/blob/107db173115cd35bfac42b5aaac9842580b9b45a/src/ewatercycle/models/hype.py#L123

Hype can be configured with forcingdir in info.txt, see http://www.smhi.net/hype/wiki/doku.php?id=start:hype_file_reference:info.txt
By setting forcingDir and mounting the forcing dir into the container we could make the ewatercycle.models.Hype.setup() method quicker and more similar to other models.

We should check that all files the model sees as forcing files are actually in the ewatercycle forcing object. If not then model could die due to misplaced files.