rename projMatrix to modelViewProjectionMatrix

[birkskyum]

as mentioned in here, the projMatrix is actually a modelViewProjectionMatrix, and it unfortunately overloads and causes confusion about the otherwise well-defined term "projection matrix". This naming is a bit more explicit / strict, which i think we need to communicate clearly.

Launch Checklist

• Confirm your changes do not include backports from Mapbox projects (unless with compliant license) - if you are not sure about this, please ask!
• Briefly describe the changes in this PR.
• Link to related issues.
• Include before/after visuals or gifs if this PR includes visual changes.
• Write tests for all new functionality.
• Document any changes to public APIs.
• Post benchmark scores.
• Add an entry to CHANGELOG.md under the ## main section.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.43%. Comparing base (b94fac4) to head (84d127e).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4215      +/-   ##
==========================================
- Coverage   87.75%   87.43%   -0.33%     
==========================================
  Files         242      242              
  Lines       33081    33081              
  Branches     2332     2182     -150     
==========================================
- Hits        29030    28923     -107     
- Misses       3083     3149      +66     
- Partials      968     1009      +41     

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[HarelM]

Do we consider this change a breaking change?
Please also add a changelog item.

[birkskyum]

Do we consider this change a breaking change? Please also add a changelog item.

I didn't consider it breaking of the public API (which is usually what we mean by breaking), since transform is internal and excluded from docs etc.

Added an entry to the changelog now.