Store detailed author information

This PR implements the long-awaited storage of detailed author information. Closes #92 (closed)

For now, here are some assorted notes on this topic. I will update this later as I progress in the work on this:

• BibLaTeX

  The BibLaTeX option is basically what has been done so far. For backwards compatibility it is important that we maintain full support for this. Maybe, we can deprecate this in the future.

  This option should not do any changes to the existing text. Therefore, it should not enforce the comma-style name separation. It must also keep the pylatexenc pass over the author names.

• YAML

  The new YAML format which explicitly expands into multiple parts. There are the following scenarios:

  • names of non-individuals will remain full strings
    • however, they must be wrapped by curly braces in their entirety
  • names of individuals must have:
    • first name(s)
    • last name(s)
    • optionally they may have:
      • one or more particles: von, de, de la, etc.
      • a suffix: Jr., Sr.
        • I don't think there can be multiple suffixes.. 🤔
    • it may be worthwhile allowing flexibility in the sense that all of these may be multiples though

  I think, we should avoid the pylatexenc pass in this case and instead leverage that we can use Unicode characters. This will also simplify inter-operability with label templates based on author names. We just need to make sure that this encoding gets run during show and export (for example). Presumably that means it gets run during stringify but I need to double check if we need to add a toggle.