Split intermediate data into base and children data

[r-ash]

Fair bit of churn, interesting bit is in types.hpp

[codecov]

Codecov Report

Patch coverage: 98.67% and project coverage change: +0.03% 🎉

Comparison is base (745e56a) 97.83% compared to head (f3ed9ae) 97.87%.

❗ Current head f3ed9ae differs from pull request most recent head 4e8947a. Consider uploading reports for the commit 4e8947a to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #32      +/-   ##
==========================================
+ Coverage   97.83%   97.87%   +0.03%     
==========================================
  Files          18       18              
  Lines        1064     1080      +16     
==========================================
+ Hits         1041     1057      +16     
  Misses         23       23              

Files Changed	Coverage Δ
inst/include/model_simulation.hpp	98.15% <98.21%> (+0.05%)	⬆️
inst/include/general_demographic_projection.hpp	100.00% <100.00%> (ø)
inst/include/hiv_demographic_projection.hpp	100.00% <100.00%> (ø)
inst/include/types.hpp	100.00% <100.00%> (ø)

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[richfitz]

LGTM, churn is at least easy to follow