rainfall multiplier for spiderweb files

[LuukBlom]

Kind of request

Adding new functionality

Enhancement Description

Currently, when adding rainfall forcing from a hurricane to SFINCS, we cannot add rainfall multiplier like for all other forcings.

Forcings with source==Track, we cannot easily change the rainfall data.
It is completely calculated by cht_cyclones, where it takes a cyclone track, creates a .spw file (deltares made data format of a moving 2D grid representing the cyclone and the wind/rainfall fields it creates). To add that to a SFINCS model, we only add the path to that file and set a config in the SfincsModel.

So we need to determine if we even want to support it and if so, how.

Task list

determine approach
implement

Use case

No response

Additional Context

No response