Fields authorization and other improvements

New features

• Fields can now be authorized through events or a authorize! method defined on the schema or nested owners.

Improvements

• Callbacks can now be called with extra arguments
• Improved how the callback by symbol finds its callable object
• Fixed issue with event last_result
• Improved chain calling after defining a field
• Fixed a problem with query_field? and similar and added query_field(name)
• Set the initial scope of ActiveRecord sources as the default_scope
• Fixed an issue with inspection of types defined on TypeMap#each_from