Adds support for org-ref cite: links to the backlinks buffer. Requires a db-rebuild, since the db schema has changed.
org-roam-graph-node-extra-config is an alist containing additional node configuration options, as per https://graphviz.gitlab.io/_pages/doc/info/attrs.html This also deprecates org-roam-graph-node-shape, which is a special case of the node options
See: https://github.com/jethrokuan/org-roam/issues/382
Addresses #357