datawizard version of unite()

[strengejacke]

Partly addresses #423

[codecov-commenter]

Codecov Report

Merging #424 (8816a9d) into main (74c0cb9) will increase coverage by 0.08%.
The diff coverage is 100.00%.

❗ Current head 8816a9d differs from pull request most recent head 9d3e728. Consider uploading reports for the commit 9d3e728 to get more accurate results

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@@            Coverage Diff             @@
##             main     #424      +/-   ##
==========================================
+ Coverage   87.94%   88.03%   +0.08%     
==========================================
  Files          65       66       +1     
  Lines        4755     4787      +32     
==========================================
+ Hits         4182     4214      +32     
  Misses        573      573              

Impacted Files	Coverage Δ
R/data_unite.R	100.00% <100.00%> (ø)

[etiennebacher]

A few comments, mostly on the argument append.

Otherwise once the description and news are updated I think this is good to go (except if you want to add the separate() version as well?)

[strengejacke]

(except if you want to add the separate() version as well?)

Maybe in a separate PR.