Unify the API for subsystem builder methods.

[Kenneth-T-Moore]

Summary

This PR expands the arguments to many of the subsystem builder methods to include aviary_inputs, phase_info, and the phase_name where they were applicable.

• Removed the define_order method from the phase_builder API. It never did anything, and that capability is a little tricky to do this way.
• Removed mission/phase_utils.py and moved the functionality into the phasebuilder base class.

Related Issues

• Resolves Refactor subsystem builder methods that can be properties #347

Backwards incompatibilities

Users will have to edit their subsystems to add the missing arguments.
In addition, an error will be raised if a subsystem builder contains the get_bus_variables method, which was renamed in an earlier PR to get_pre_mission_bus_variables.

New Dependencies

None