Use timestamps for attribute updates

[TimSylvester]

Attribute vectors and buffers should track the last time at which they were updated. For efficiency, the vectors still use a private dirty flag internally, to avoid querying the time for each individual value added, which is checked at the end of the update process and the update time adjusted appropriately. And non-shared attribute data still uses a simple dirty flag.

Also incorporates #2615

Resolves #2628

[github-actions]

Bloaty Results (iOS) 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.2% +28.8Ki  +0.2% +32.0Ki    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results-ios/pr-2629-compared-to-main.txt

[github-actions]

Bloaty Results 🐋

Compared to main

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +0.0% +50.0Ki  +0.0% +2.68Ki    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-2629-compared-to-main.txt

Compared to d387090 (legacy)

    FILE SIZE        VM SIZE    
 --------------  -------------- 
   +27% +31.0Mi  +420% +25.1Mi    TOTAL

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/bloaty-results/pr-2629-compared-to-legacy.txt

[github-actions]

Benchmark Results ⚡

Benchmark                                                     Time             CPU      Time Old      Time New       CPU Old       CPU New
------------------------------------------------------------------------------------------------------------------------------------------
OVERALL_GEOMEAN                                            +0.0037         +0.0039             0             0             0             0

Full report: https://maplibre-native.s3.eu-central-1.amazonaws.com/benchmark-results/pr-2629-compared-to-main.txt

[TimSylvester]

The codecov results seem spurious