Enhanced BibTeX reStructuredText/Sphinx citation roles - research and planning

This ticket is for the research and planning of enhanced bibtex citation support for enhanced BibTeX citation roles for reStructuredText/Sphinx projects. This ticket should produce a plan that answers these basic questions:

• What roles are needed? For example, cite currently produces numeric in-text citations. We'd like to see in-text citations that show the document handle and even the title. We might also want author-year type citations for publications.
• How should these roles be integrated with sphinxcontrib-bibtex? For example, it's possible that we might use sphinxcontrib-bibtex as a library for an extension that we package with documenteer.