Attach model_creation and solve_complete timestamps to model data attrs

[sjpfenninger]

Fixes #583

Summary of changes in this pull request:

• Attach model_creation and solve_complete timestamps to model data attrs

Reviewer checklist:

• Test(s) added to cover contribution
• Documentation updated
• Changelog updated
• Coverage maintained or improved

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.92%. Comparing base (872978d) to head (ebbfa66).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #586      +/-   ##
==========================================
+ Coverage   95.85%   95.92%   +0.06%     
==========================================
  Files          24       24              
  Lines        3619     3628       +9     
  Branches      788      723      -65     
==========================================
+ Hits         3469     3480      +11     
+ Misses         86       84       -2     
  Partials       64       64              

Files	Coverage Δ
src/calliope/model.py	93.72% <100.00%> (+0.07%)	⬆️
src/calliope/postprocess/postprocess.py	98.24% <100.00%> (+4.69%)	⬆️
src/calliope/util/logging.py	94.44% <100.00%> (+0.56%)	⬆️

[brynpickering]

I have come across an issue in previous runs that this should solve. If there is any lag between calling model.build() and model.solve(), you get an artificially extended solve time. The logger should also capture when model.build() and model.run() were called. Then build/solve time is the difference between finish and start times.

[sjpfenninger]

Since run is deprecated, we probably don't want to start logging it? Maybe we add the following timestamps to the results?

• timestamp_build_started
• timestamp_build_complete
• timestamp_solve_started
• timestamp_solve_complete

[brynpickering]

Sorry, yeah, mistype on my part. Those logging timestamps sound good.

[sjpfenninger]

Now have five timestamps (in order of occurrence):

• timestamp_model_creation: at the start of Model.__init__()
• timestamp_build_started: at the start of Model.build()
• timestamp_build_complete: at the end of Model.build()
• timestamp_solve_started: at the start of Model.solve()
• timestamp_solve_complete: at the end of Model.solve()