Minor edits to QRF implementation

[gavinevans]

Addresses https://github.com/metoppv/mo-blue-team/issues/877

Description
This PR contains minor edits related to:

• Trying to correct the mailmap, although this is difficult to test.
• Enabling the quantile-forest module to be optional.

Testing:

• Ran tests and they passed OK
• Added new tests for the new feature(s)

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

❌ Patch coverage is 50.00000% with 11 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (mobt_877_implement_qrf@de4b761). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
...r/calibration/quantile_regression_random_forest.py	54.54%	5 Missing ⚠️
...oad_and_apply_quantile_regression_random_forest.py	62.50%	3 Missing ⚠️
...oad_and_train_quantile_regression_random_forest.py	0.00%	3 Missing ⚠️
❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@                    Coverage Diff                    @@
##             mobt_877_implement_qrf      #15   +/-   ##
=========================================================
  Coverage                          ?   96.19%           
=========================================================
  Files                             ?      142           
  Lines                             ?    14077           
  Branches                          ?        0           
=========================================================
  Hits                              ?    13542           
  Misses                            ?      535           
  Partials                          ?        0           

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.