Deprecate particle emitter, and use scatter ratio in new particle mes…

[nkoenig]

🎉 New feature

Summary

Use the particle_scatter_ratio in the particle emitter message available in fortress. This also starts the process of tick-tocking the ParticleEmitterSystem.

Test it

Run the test suite.

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• 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

[codecov]

Codecov Report

Merging #986 (dd75161) into main (f274863) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main     #986      +/-   ##
==========================================
- Coverage   64.51%   64.50%   -0.02%     
==========================================
  Files         246      246              
  Lines       19746    19743       -3     
==========================================
- Hits        12740    12735       -5     
- Misses       7006     7008       +2     

Impacted Files	Coverage Δ
src/Conversions.cc	83.70% <100.00%> (-0.06%)	⬇️
src/systems/particle_emitter2/ParticleEmitter2.cc	55.40% <0.00%> (-2.71%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f274863...dd75161. Read the comment docs.

[nkoenig]

The failing builds look unrelated to this PR.

[iche033]

looks good to me.