Citation File Format

[paulpestov]

          @mathias-goebel, @stexandev and I discussed about this. Our solution will be as follows:

• there will be a separate field in the Support Object for a CFF file. TIDO can then take this file and render it in different formats (e.g. Chicago style, BibTeX, …)
• since the Support Object is on Manifest level, the Item will be considered in the URL present in the citation. This URL has to be fetched and inserted by the client.
• We agree on making the citation key configurable in the metadata panel options

Originally posted by @mweidling in #470 (comment)