[CURA-11255] improve engine logging

[wawanbreton]

Content of modifications :

• Use spdlog::stopwatch instead of custom time functions to measure time (which fixes wrong timing reports, at least on Linux)
• Make timing report consistent and more readable:

  [2023-11-03 11:48:47.158] [info] Progress: inset+skin accomplished in 2.4762119999998s
  ===>
  [2023-11-03 11:48:47.158] [info] Progress: inset+skin accomplished in 2.476s

• Add timing report for layer export processing, which is usually the longest step. Only the steps reported longer than 10ms (configurable by code) are displayed, and only the layers reported longer than 100 ms are fully displayed:

  [2023-11-07 10:45:40.073] [info] ┌ Layer export [244] accomplished in 0.139s
  [2023-11-07 10:45:40.073] [info] ├── Init:   0.012s
  [2023-11-07 10:45:40.073] [info] └── Mesh 0: 0.119s
  [2023-11-07 10:45:40.076] [info] Skipped time reporting for layers [245...246]
  [2023-11-07 10:45:40.076] [info] ┌ Layer export [246] accomplished in 0.113s
  [2023-11-07 10:45:40.076] [info] └── Mesh 0: 0.109s
  [2023-11-07 10:45:40.088] [info] ┌ Layer export [247] accomplished in 0.110s
  [2023-11-07 10:45:40.088] [info] └── Mesh 0: 0.104s
  [2023-11-07 10:45:40.090] [info] ┌ Layer export [248] accomplished in 0.108s
  [2023-11-07 10:45:40.090] [info] └── Mesh 0: 0.102s
  [2023-11-07 10:45:40.395] [info] Skipped time reporting for layers [249...309]
  [2023-11-07 10:45:40.395] [info] ┌ Layer export [309] accomplished in 0.109s
  [2023-11-07 10:45:40.395] [info] └── Mesh 0: 0.106s

The last added logging make it very easy to see when something is wrong during the export step, although it does get into the deep details.

[github-actions[bot]]

Unit Test Results

26 tests  ±0   26 :heavy_check_mark: +1   15s :stopwatch: +3s   1 suites ±0     0 :zzz: ±0    1 files   ±0     0 :x:  - 1 

Results for commit c07a0a17. ± Comparison against base commit a58cb53e.

:recycle: This comment has been updated with latest results.