Drivers should be optional dependencies?

[Huite]

get_driver currently looks like this:

    from imod_coupler.drivers.metamod.config import MetaModConfig
    from imod_coupler.drivers.metamod.metamod import MetaMod
    from imod_coupler.drivers.ribamod.config import RibaModConfig
    from imod_coupler.drivers.ribamod.ribamod import RibaMod

    if base_config.driver_type == "metamod":
        metamod_config = MetaModConfig(config_dir=config_dir, **config_dict["driver"])
        return MetaMod(base_config, metamod_config)
    elif base_config.driver_type == "ribamod":
        ribamod_config = RibaModConfig(config_dir=config_dir, **config_dict["driver"])
        return RibaMod(base_config, ribamod_config)
    else:
        raise ValueError(f"Driver type {base_config.driver_type} is not supported.")

It should probably be more like this?

    if base_config.driver_type == "metamod":
        from imod_coupler.drivers.metamod.config import MetaModConfig
        from imod_coupler.drivers.metamod.metamod import MetaMod

        metamod_config = MetaModConfig(config_dir=config_dir, **config_dict["driver"])
        return MetaMod(base_config, metamod_config)
    elif base_config.driver_type == "ribamod":
        from imod_coupler.drivers.ribamod.config import RibaModConfig
        from imod_coupler.drivers.ribamod.ribamod import RibaMod

        ribamod_config = RibaModConfig(config_dir=config_dir, **config_dict["driver"])
        return RibaMod(base_config, ribamod_config)
    else:
        raise ValueError(f"Driver type {base_config.driver_type} is not supported.")

I don't think we want to make ribasim mandatory for everyone who wants to run MetaSWAP.