Add Ultimate Neutral SOCD Optional Binary

[jugeeya]

Neutral SOCD is legal in Smash Ultimate: https://smashworldtour.com/wp-content/uploads/2021/02/SWT-2021-Rulebook-2020.2.16.pdf

If two opposing cardinal directions are activated simultaneously, the
following controller-side SOCD resolution methods are permitted:

• A neutral input (neither cardinal direction) is produced
• The more recent cardinal direction overrides the less recent
  cardinal direction and the less recent cardinal direction is
  deactivated until manually activated again.

If two opposing cardinal directions are first activated simultaneously, the
controller may either produce a neutral input or may give priority to one of
the cardinal directions in a predetermined manner

• Converted CMake file to have a loop with environment variables for ease of onboarding new ones such as Ult Neutral SOCD. I think Adding rumble info to images/README, moving melee analog values to #defines and optional neutral SOCD for melee. #26 could also use this to add MELEE_NEUTRAL easily.
• Added Neutral SOCD for Ultimate based on ULT_NEUTRAL environment variable
• Update Github Action to upload all three artifacts with appropriate naming