Add support for ESGF Reference Datasets (obs4MIPS) (qv56) to ESMValTool-workflow

[rbeucher]

We need to integrate support for the ESGF Reference Datasets (project qv56) into the ESMValTool-workflow. This will involve modifying configuration files to enable the use of these datasets for climate model analysis and forcing.

Tasks:

Update ESMValTool configuration files to include the qv56 project.
Confirm the dataset's format and evaluate whether CMORisation is necessary. Based on preliminary assessment, the data may already be formatted correctly for use without CMORisation.
Test the datasets with existing ESMValTool recipes to ensure proper compatibility and functionality.