Feat/Data handler to save data #651

All 389 tests pass, 3 skipped in 23s

392 tests ±0 389 ✔️ ±0 23s ⏱️ -1s
    1 suites ±0     3 💤 ±0
    1 files ±0     0 ❌ ±0

Results for commit c5ed718. ± Comparison against earlier commit 99c1853.