VIVO-2006: Add CITATION.cff to Github repo

[chenejac]

Christian Hauschke (Migrated from VIVO-2006) said:

• Put the citation recommendation in the new Github citation widget.

  • Remove citation recommendation from readme.

  Conlon et al., (2019). VIVO: a system for research discovery. Journal of Open Source Software, 4(39), 1182, [https://doi.org/10.21105/joss.01182]

[chenejac]

Christian Hauschke said:

[https://github.com/vivo-project/VIVO/pull/247] - some issues remain, see PR discussion.