Generalized mask: use any given dataset cube to construct a mask to be applied to all other dataset cubes

[valeriupredoi]

Description

Closes #1804

Link to documentation: to be added

---

Before you get started

• ☝ Create an issue to discuss what you are going to do

Checklist

It is the responsibility of the author to make sure the pull request is ready to review. The icons indicate whether the item will be subject to the 🛠 Technical or 🧪 Scientific review.

• 🧪 The new functionality is relevant and scientifically sound
• 🛠 This pull request has a descriptive title and labels
• 🛠 Code is written according to the code quality guidelines
• 🧪 and 🛠 Documentation is available
• 🛠 Unit tests have been added
• 🛠 Changes are backward compatible
• 🛠 Any changed dependencies have been added or removed correctly
• 🛠 The list of authors is up to date
• 🛠 All checks below this pull request were successful

---

To help with the number pull requests:

• 🙏 We kindly ask you to review two other open pull requests in this repository

[codecov]

Codecov Report

Attention: 2 lines in your changes are missing coverage. Please review.

Comparison is base (989839f) 93.74% compared to head (739cd61) 93.73%.

Files	Patch %	Lines
esmvalcore/preprocessor/_mask.py	81.81%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1803      +/-   ##
==========================================
- Coverage   93.74%   93.73%   -0.01%     
==========================================
  Files         238      238              
  Lines       13153    13164      +11     
==========================================
+ Hits        12330    12339       +9     
- Misses        823      825       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.