Fix indexing error for 0-dimensional HDF5 datasets

[dweindl]

• Refactor ProfileResultHDF5Writer to be more readable
• Raise more informative error if writing to HDF5 fails
• Don't index 0-dimensional datasets (Fixes store.write_result: ValueError: 1 indexing arguments for 0 dimensions #1205)

[codecov-commenter]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (a6e300f) 81.40% compared to head (a20c703) 81.38%.
Report is 1 commits behind head on develop.

Files	Patch %	Lines
pypesto/store/save_to_hdf5.py	87.50%	2 Missing ⚠️

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Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1206      +/-   ##
===========================================
- Coverage    81.40%   81.38%   -0.02%     
===========================================
  Files          148      148              
  Lines        11785    11794       +9     
===========================================
+ Hits          9593     9598       +5     
- Misses        2192     2196       +4     

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[PaulJonasJost]

Do we perhaps need more extensive testing on the histories?

[dweindl]

Do we perhaps need more extensive testing on the histories?

Wouldn't hurt. But if we'd just fix issues instead of re-running tests we should be fine :)