Standardize required altitude rate naming

Desired capability or behavior.

Summary of Issue

In some places in Aviary, we have multiple names for effectively the same thing: required_altitude_rate and roc_at_toc.
Pick one name -- probably the former as verbosity is helpful -- and use it everywhere.

Issue Type

• Bug
• Enhancement
• Code Cleanup
• Docs
• Miscellaneous

Is your feature request related to a problem? Please describe.

Thinking more about this now, this is slightly more complex than just renaming.
I'll put my thoughts here.

GASP- and FLOPS-based missions handle rate of climb at top of climb differently. Aviary currently has no constraint on the GASP side but it exists in the input decks. FLOPS-based has required_altitude_rate come in at the phase_info level. This is valid for any phase and is enforced as a path constraint across the whole phase, not just climb.

We might as well rework this so that:

• the required altitude rate is available to be enforced anywhere, not just a phase called climb
• it's handled in the same way for all types of missions with a constraint at the add_design_variables() method level from methods_for_level2.py
• to do this, we'd need to compute ALTITUDE_RATE_MAX as part of the GASP equations of motion, which is not currently the case

Associated Bug Report

No response