Restore CXX_STANDARD 17 and test gz-cmake PR

[scpeters]

🦟 Bug fix

Testing gazebosim/gz-cmake#274.

Summary

Restore CXX_STANDARD export in core library since it uses c++ features in API, and also test a gz-cmake PR using ci_matching_branch/ with gazebo-tooling/gazebodistro@2eb328d and osrf/homebrew-simulation@b1acded

Checklist

• Signed all commits for DCO
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge and edit the commit message to match the pull request summary while retaining Signed-off-by messages.

[codecov]

Codecov Report

Merging #1586 (fbbe755) into main (a3cbd8c) will decrease coverage by 0.03%.
The diff coverage is 99.31%.

@@            Coverage Diff             @@
##             main    #1586      +/-   ##
==========================================
- Coverage   63.62%   63.59%   -0.04%     
==========================================
  Files         330      330              
  Lines       25787    25925     +138     
==========================================
+ Hits        16408    16487      +79     
- Misses       9379     9438      +59     

Impacted Files	Coverage Δ
include/gz/sim/EventManager.hh	79.16% <ø> (ø)
include/gz/sim/Util.hh	100.00% <ø> (ø)
include/gz/sim/components/Factory.hh	97.53% <80.00%> (-1.18%)	⬇️
include/gz/sim/EntityComponentManager.hh	100.00% <100.00%> (ø)
include/gz/sim/Link.hh	100.00% <100.00%> (ø)
include/gz/sim/Model.hh	100.00% <100.00%> (ø)
include/gz/sim/SdfEntityCreator.hh	100.00% <100.00%> (ø)
include/gz/sim/Server.hh	100.00% <100.00%> (ø)
include/gz/sim/ServerConfig.hh	100.00% <100.00%> (ø)
include/gz/sim/SystemLoader.hh	100.00% <100.00%> (ø)
... and 131 more

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