Refactor and improve Middleware.staticDirectory

[radex]

• Refactor Middleware.staticDirectory
  • 80 LOC → 30 LOC
  • Avoid explicit imperative loops
  • Helper method String.taylor_pathComponents to replace previous loops
  • Helper method Middleware.matchPaths to compare path component arrays
• Define staticDirectory(bundle:) in terms of staticDirectory(directory:)
  • Avoids ambiguity (can't pass both or none)
  • Removes unnecessary code
  • Automatic foo/ → foo/index.html matching now works with bundle variant