[Ovid] Almost a complete rewrite

Use OVID Tagged translator for imports
Attach PDFs where available
Needs some more testing, but works pretty much everywhere, except for PDF view pages _if_ they were accessed from the individual item page and not from search results. Doesn't appear to be possible to reconstruct metadata POST parameters that way. Might consider going to a different page in those cases to fetch metadata.

Author: aurimasv