Fixes to JDatabundle, JWiringService

[nathanwbrei]

Behavior change

• Remove CallbackStyle::DeclarativeMode: This was originally added to be consistent with JOmniFactory, but never used. The callback style suffers from several problems:
  1. The name clashes with JOmniFactory::ChangeRun. Now that JOmniFactory inherits from JFactory, this causes warnings about a non-virtual method overriding a virtual one.
  2. The arguments are ambiguous, causing user confusion and clang-tidy complaints
  3. It won't generalize to multi-level topologies, compared to JEvent::GetParent.

Bugfixes

• Fix memory leaks relating to JDatabundle upcast functions
• Fix bug in JOutput::EulerianStore due to JLightweightDatabundle copy constructor
• Unit test suite passes LeakSanitizer for the first time

Refactoring

• JOmniFactory inherits from JFactory
• JWiringService is substantially more testable