Bugfix: Set equal chunking for shapes and dataset

[CSSFrancis]

Description of the change

I noticed this morning that I was having issues loading larger arrays of vectors using the distributed-dask backend.

The problem is that the shape array is not saved with the same chunking scheme so when you try to load the shape array you have to split the memory between all of the different cores. This is slow, probably partially because dask doesn't know the size of the array which

Progress of the PR

• Change implemented (can be split into several points),
• add a changelog entry in the upcoming_changes folder (see upcoming_changes/README.rst),
• Check formatting of the changelog entry (and eventual user guide changes) in the docs/readthedocs.org:rosettasciio build of this PR (link in github checks)
• add tests,
• ready for review.

Minimal example of the bug fix or the new feature

pks = s.find_peaks()
pks.save("ragged.zspy")
pks = hs.load("radded.zspy", lazy=True)
pks.compute() 

For a 1024x1024 array of peak positions the old saving scheme took 1 minute to load with the new scheme that becomes ~1 second with the new scheme.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (c85f768) 86.22% compared to head (68b72bf) 86.17%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #211      +/-   ##
==========================================
- Coverage   86.22%   86.17%   -0.05%     
==========================================
  Files          82       82              
  Lines       10549    10548       -1     
  Branches     2293     2293              
==========================================
- Hits         9096     9090       -6     
- Misses        933      938       +5     
  Partials      520      520              

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[ericpre]

Looks good, do you want to add a changelog entry

[CSSFrancis]

Looks good, do you want to add a changelog entry

Yea I'll add a changelog entry, but I might just try it out today to make sure there aren't any other bugs related to this!

[ericpre]

Update the comment to also mention the reason?

[ericpre]

Ping @CSSFrancis! 😉

Just to avoid conflicts with #213.

[CSSFrancis]

Ping @CSSFrancis! 😉

Just to avoid conflicts with #213.

@ericpre Oops let me add that comment and then we can merge. This has been working for the last week (at least well enough that I forgot about coming back to the fix :))

[ericpre]

And a changelog entry please!