Add synchronised partitioning of multiple objects

[ablaom]

Resolves #682

[codecov-commenter]

Codecov Report

Merging #696 (6c1894d) into for-0-point-19-release (21829e7) will increase coverage by 0.04%.
The diff coverage is 100.00%.

@@                    Coverage Diff                     @@
##           for-0-point-19-release     #696      +/-   ##
==========================================================
+ Coverage                   86.56%   86.60%   +0.04%     
==========================================================
  Files                          37       37              
  Lines                        3342     3352      +10     
==========================================================
+ Hits                         2893     2903      +10     
  Misses                        449      449              

Impacted Files	Coverage Δ
src/data/data.jl	95.41% <100.00%> (+0.46%)	⬆️

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