Collect DataCite metadata on linked Software publications

In addition to the solution with scholix metadata (issue #23 (closed)), the resource type could be complemented and validated using the DataCite API:

e.g. https://api.datacite.org/dois/10.18129/b9.bioc.rcas

(careful: I found examples where the resource is falsely registered as type "dataset: see, e.g., https://api.datacite.org/dois/10.13140/rg.2.2.32053.47840)