Refactor ViewNameParser

[joeholdcroft]

• It does too much. Consider moving a bunch of this logic elsewhere.
• The "default dirs" functionality seems backwards. Could it not just be an array of directories to check in? Then the view override dir can be at the end and it will then always replace the views in that way.
  • Alternatively could we do something where things can add functions that are passed the parsed reference instance. Then Cog could define a declaration to look for the standard view, and a view override also?