Update DrugBank with its vocabulary data

[erikyao]

Thanks to @rjawesome, we now know the existence of DrugBank Vocabulary data. They can be used to update our Drugbank API.

P.S. there is an SDF file of drug structures as well on the above page.

[ravila4]

@newgene @erikyao It's great that we can include some Drugbank data in MyChem API. The csv file does not contain all the information that the old data had, so the parser needs to be completely rewritten. Perhaps we can archive the old mongodb collection and parser, in case we ever need it for internal use.

Regarding the SDF structure file, we don't store 3D structure information from any other datasources, so I don't think we will be parsing it.

[erikyao]

@ravila4 sounds good to me. Also we can try introducing it as a new individual plugin, rather than overwriting the old one.