Add Dockerfile and Makefile to create ocr-d dockerimage

[joschrew]

This PR adds a Dockerfile and Makefile to create a dockerimage for this processor. Ideally all OCR-D processors offer the same way to create an image for them, which is currently missing in this repo. I am not sure though if this is desired here as well, because it seems to me dinglehopper has slightly other layout as a "normal" ocr-d processor has. Dinglehopper seems also to be supposed to be used detached from ocr-d. That's why I created a draft PR at first.