[Speed] Hackathon speed improvements

[LDTalbot]

Description
PR for computational speed improvements during hackathon.

Changes

• Refactor for updating mass and momentum within single loop & mutex (previous separate update functions still available). Fixes CPU idle time every step when using OpenMP.
• Test effects with serial
• Test effects with OpenMP
• Test effects with MPI
• Test effects with scaling model size
• Write tests (current tests cover this)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.76%. Comparing base (c523c20) to head (fa8bbc7).

Additional details and impacted files

@@           Coverage Diff           @@
##           master      #96   +/-   ##
=======================================
  Coverage   95.76%   95.76%           
=======================================
  Files         244      244           
  Lines       51307    51317   +10     
=======================================
+ Hits        49130    49140   +10     
  Misses       2177     2177           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.