Adds unit conversion to read_pyaro

[dulte]

Change Summary

After some problems with the EEA reader and units, I've added unit conversion to read_pyaro

Checklist

• Start with a draft-PR
• The PR title is a good summary of the changes
• PR is set to AeroTools and a tentative milestone
• Documentation reflects the changes where applicable
• Tests for the changes exist where applicable
• Tests pass locally
• Tests pass on CI
• At least 1 reviewer is selected
• Make PR ready to review

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.98%. Comparing base (4a7bece) to head (f7a088f).
Report is 16 commits behind head on main-dev.

Additional details and impacted files

@@             Coverage Diff              @@
##           main-dev    #1343      +/-   ##
============================================
+ Coverage     78.97%   78.98%   +0.01%     
============================================
  Files           136      136              
  Lines         20815    20831      +16     
============================================
+ Hits          16438    16454      +16     
  Misses         4377     4377              

Flag	Coverage Δ
unittests	78.98% <100.00%> (+0.01%)	⬆️

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[dulte]

It is more or less done. But I get strange results with my calculated factor for the conversion between mg S/l and ugm-3. The resulting observations from EEA then gets 6 order of magnitude larger than the model. So there is something I don't understand with the mgS/l units...

[dulte]

This might be the wrong way of handling the units. Will remove PR as of now