[FEATURE] Enhance Citation functionality

[freephile]

Is your feature request related to a problem? Please describe.

Citation functionality out of the box is largely non-existent. Make it better.

Describe the solution you'd like

Include content that solves the problem quickly e.g. a Help: page linking to the RefScript bookmarklet; or test and implement a full-blown Citoid services.

Describe alternatives you've considered

See https://wiki.freephile.org/wiki/Citations