Clean up utilities

[peterdesmet]

As mentioned in https://github.com/inbo/alien-species-checklist/pull/71, we should clean up /utilities

Decisions:

• combination_maker: keep in utilities, but rename to something like combine_vocabulary_values + remove habitats.txt output. Discussed in #58
• concatenation: is a notebook to explain csvcat. The way to call csvcat is mentioned in the README, so I think we can remove this directory
• merge_controlled_vocabularies: move and rename to notebooks/1-stijnvanhoey-map_vocabularies.ipyth and maybe document a bit further. Note that the vocabularies + their mapping is now at https://github.com/inbo/alien-species-checklist/tree/rinse-out-of-scope/data/vocabularies
• viz_pathways: move and rename to notebooks/0-stijnvanhoey-viz-pathways.ipyth. I would remove the output images + files if possible.

[stijnvanhoey]

The notebooks moved, but their source data files are changed, both in location as structure. I'm keeping this open in order to adapt 1-stijnvanhoey-map_vocabularies.ipynb in the implementation itself as well.

[stijnvanhoey]

restructuring of the repo finalised, closing