Restore message generation pipeline and generate message libraries

[mjcarroll]

This it the final rework of the message generation pipeline for Harmonic.

After trying multiple approaches, we decided to keep the messages in one location and generate the library as part of gz-msgs to derisk the long term supported Harmonic release.

This PR adds the new message generation pipeline, but uses it internally to keep the API similar to previous releases.

Also needs: gazebosim/gz-sensors#375
Also needs: gazebosim/gz-gui#563

[codecov]

Codecov Report

Merging #368 (c1fea4b) into main (a8b2d84) will increase coverage by 0.17%.
The diff coverage is 98.13%.

❗ Current head c1fea4b differs from pull request most recent head 7a062af. Consider uploading reports for the commit 7a062af to get more accurate results

@@            Coverage Diff             @@
##             main     #368      +/-   ##
==========================================
+ Coverage   97.03%   97.21%   +0.17%     
==========================================
  Files           9       27      +18     
  Lines        1081     1150      +69     
==========================================
+ Hits         1049     1118      +69     
  Misses         32       32              

Files Changed	Coverage Δ
core/generator/generator_main.cc	100.00% <ø> (ø)
...re/include/gz/msgs/detail/PointCloudPackedUtils.hh	94.80% <ø> (ø)
core/src/gz.cc	90.47% <ø> (ø)
core/src/DynamicFactory.cc	87.09% <87.09%> (ø)
core/src/Factory.cc	87.50% <87.50%> (ø)
...re/include/gz/msgs/convert/SphericalCoordinates.hh	92.85% <92.85%> (ø)
core/src/MessageFactory.cc	94.44% <94.44%> (ø)
core/generator/Generator.cc	92.64% <100.00%> (ø)
core/include/gz/msgs/Factory.hh	100.00% <100.00%> (ø)
core/include/gz/msgs/MessageFactory.hh	100.00% <100.00%> (ø)
... and 17 more

[mjcarroll]

@j-rivero is there any way to run PR jobs against jammy+? In this case, the protobuf version is missing some APIs in focal

[azeey]

You can ignore the Focal builds. The Jammy job is already in the PR( gz-msgs-ci-pr_any-jammy-amd64) . I don't think we can remove the Focal jobs from an open PR, but new PRs should only run on Jammy on Jenkins.

[azeey]

Looks great! Just a few more minor comments.

[azeey]

Looks great! Thanks for iterating.

gazebosim/gz-sim#2087 probably needs to be merged before we merge this.

[mjcarroll]

gazebosim/gz-sim#2087 probably needs to be merged before we merge this.

2087 depends on this one being merged/released.

[azeey]

gazebosim/gz-sim#2087 probably needs to be merged before we merge this.

2087 depends on this one being merged/released.

Okay, let's merge this then.