refactor: webgl isolation

[birkskyum]

• rename /gl to /webgl
• move all webgl draw files to /webgl/draw
• move all webgl program files to /webgl/program/
• updates all the imports in the remaining files
• update painter to use a drawFunctions object, so for now draw.circle will reach the webgl drawCircle, but it gives the option for us to introduce a webgpu draw function.

Related to

• WebGPU support #2606
• [PoC] WebGPU Backend #7411

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]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.86%. Comparing base (789b3da) to head (e41a3c5).
⚠️ Report is 7 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7422   +/-   ##
=======================================
  Coverage   92.86%   92.86%           
=======================================
  Files         288      289    +1     
  Lines       23998    24001    +3     
  Branches     5095     5095           
=======================================
+ Hits        22286    22289    +3     
  Misses       1712     1712           

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[HarelM]

I've added a minor comment, otherwise looks good.