complete refactor of postprocess

[clarkliming]

close #314

move prune/sort/null_report to post processings

other things changed:

1. move scda to imports (avoid errors when user try to run examples without scda)
2. create data with syn_test_data to increase the speed
3. add helper script for testthat to avoid repeated call of syn_test_data()
4. create null_report object and export it
5. put "no observations.." in content instead of header

decorations, should also go into "post-processings" but currently we have them in main. we can always change it later.

[github-actions]

Unit Tests Summary

  1 files    9 suites   22s ⏱️
27 tests 25 ✔️   2 💤 0 ❌
72 runs  51 ✔️ 21 💤 0 ❌

Results for commit a690f35.

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[BFalquet]

I love it! Thank you for the work. We could think of moving syn_test_data() to data-raw folder, save syn_data in an rds file and document it in data.R

[BFalquet]

Suggested change