Dymo Letratag holder for Skadis

I didn´t find a Dymo Letratag holder for the Skadis system that I 100% liked (low filament usage, easy to print, using supports only for the hooks), but the model by MikeyMike_was_already_taken came close enough (which is a remix itself, I could also have used the original). The following changes were made:

• I added Skadis hooks to the model. I'm not a fan of the universal hook system.
• I removed parts from the top and bottom to save a decent amount filament (the supports are only needed for the hooks now), to remove all traces of the universal hook system and make the model easier to print.
• I removed a bit from back in order to make it fully flat and save a tiny bit of filament.