macOS Timestamp migration

[puffyCid]

This PR migrates timestamps for macOS artifacts to ISO RFC 3339 format.

Also includes some updates and bug fixes

[codecov]

Codecov Report

Attention: Patch coverage is 89.51049% with 15 lines in your changes missing coverage. Please review.

Project coverage is 84.78%. Comparing base (8f77c8f) to head (303005c).

Files	Patch %	Lines
core/src/artifacts/os/macos/execpolicy/policy.rs	0.00%	14 Missing ⚠️
core/src/artifacts/applications/safari/plist.rs	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #150      +/-   ##
==========================================
+ Coverage   84.73%   84.78%   +0.05%     
==========================================
  Files         474      475       +1     
  Lines       53491    53549      +58     
==========================================
+ Hits        45323    45400      +77     
+ Misses       8168     8149      -19     

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