The markup resource is focused on the annotation of geometric models
(i.e., "marking up the geometry").

Some related changes include:

+ Do not fail when geometry is not provided.
  Some resources inherit `smtk::geometry::Resource` but have
  no geometry and that's alright. Avoid VTK errors/warnings
  when this happens.
+ Graph-resource grammar improvements.

  + Accept `any` or `*` queries to mean that any object matches.
  + Ensure that an empty query is parsed properly (since now
    all of the query string must be consumed by a rule, provide a
    rule that matches zero or more spaces) and that it returns false
    for all components.
  + Fix the JSON node serializer to use a proper filter grammar
    (where previously parsing would fail, thus reporting every node
    as matching… but then the exact type-name check would filter
    the list down to what was needed).
  + Fix several tests that used improper query-filters.

+ Add component names and tr...