edited __init__.py in scopesim_templates to include the metis import

[JenniferKarr]

As in the title, so that we can use the metis laser_source and pinhole_mask templates

[hugobuddel]

Feel free to merge this.

I don't thing such imports in __init__.py are necessary though, I never write them and everything just works fine.

[teutoburg]

I'm merging this, because while it might not be necessary, I don't think it hurts either, so why not...