Colocate UEMEP station data

[thorbjoernl]

Change Summary

• Script for creating a colocated data object for UEMEP station data (currently colocating against EBAS hourly data).
• Implements a validate_structure function that does some additional checking of ColocatedData.data based on things I noticed (I haven't added it as part of pydantic validation because a lot of tests break due to using invalid, dummy objects).
• Preview: https://aeroval-test.met.no/thlun/pages/evaluation/?project=uemep_test&experiment=20250207&parameter=conco3&station=Europe&model=uemep&season=All#

Related issue number

closes #1175

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

Attention: Patch coverage is 58.22785% with 33 lines in your changes missing coverage. Please review.

Project coverage is 78.22%. Comparing base (3867e4b) to head (2b0350a).
Report is 79 commits behind head on main-dev.

Files with missing lines	Patch %	Lines
pyaerocom/colocation/colocated_data.py	35.29%	22 Missing ⚠️
pyaerocom/io/uemep/model_variables.py	0.00%	8 Missing ⚠️
pyaerocom/aeroval/coldatatojson_engine.py	0.00%	1 Missing ⚠️
pyaerocom/colocation/colocation_utils.py	80.00%	1 Missing ⚠️
pyaerocom/io/uemep/__init__.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           main-dev    #1508      +/-   ##
============================================
- Coverage     78.49%   78.22%   -0.28%     
============================================
  Files           140      142       +2     
  Lines         21299    21448     +149     
============================================
+ Hits          16719    16778      +59     
- Misses         4580     4670      +90     

Flag	Coverage Δ
unittests	78.22% <58.22%> (-0.28%)	⬇️

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