export: add BibTeX export option

[RaoOfPhysics]

For example, on http://opendata.cern.ch/record/613

Redirects to http://opendata.cern.ch/record/Unknown%20variable:%20CFG_BASEfa%20fa-_URL%3C/span%3EERVER_INFO%20var='CFG_SITE_RECORD'/%3E/613/export/hx?ln=en

cc: @jottCern

[espacial]

Apart from the broken link, we have to decide how to export...

• Should we use @ misc or @ article as type?
  The vocabulary is reduced, and the best match would be @ misc (sadly). The advantages of @ article are that the standard fields cover what we need.
• How do we generate the keys?
  The common ways are author:year:random. Maybe we can go for something like collaboration:year:recid.
• What fields do we export?
  For sure: author, title, DOI, publication date... something else?

[tiborsimko]

@pamfilos Please remove "Export" pop-up from the live site until we have some workable version of BibTeX export in place. Also, the exportable formats should be "actionable", or "process-friendly" to machines, which the current pop-up modal window is not. (E.g. JSON in "Overview" is not really JSON, e.g. each format should have their canonical machine-consumable URL, etc). It would be better to revert back to usual Invenio's /record/123/export/foo technique.

[tiborsimko]

The MARC export option was amended, the BibTeX export option will be added later.

[suenjedt]

Similar discussion on INSPIRE and in Dataverse team. Lets find a common solution that makes sure a DOI is included in the output etc

[tiborsimko]

CC-ing @lnielsen who has similar BibTeX data set and program mapping topics on Zenodo

[suenjedt]

@tiborsimko @hjhsalo is this part of the template sprint (bibtex export) anyway?

[tiborsimko]

See also #1324.