add datacite clients

.gitignore

0-collect-data/datacite-dois.txt

0-collect-data/datacite.py

0-collect-data/z-datacite-demo.ipynb

1-enrich-with-datacite/concatenet-enrich-dois.py

1-enrich-with-datacite/datacite-parser-instructions.json

1-enrich-with-datacite/z_personal_functions.py

2-produce-graph/hist--datasets-by-year.png

2-produce-graph/hist-quantity-by-year.py

2-produce-graph/pie--datacite-client.png

2-produce-graph/pie-datacite-client.py

dois-uga.csv