Spatial interpolation added to find_variable to allow mesh different from the original mesh

Reference issue

N/A

Description

This merge request adds the functionality to perform interpolation in space when using find_variable for time varying data. This means that data on a different mesh can be used as input in TELEMAC in 2D (3D is not available yet). This is the follow up of a previous merge request, in which this functionality was already included, but which needed to be split into two merge requests, one for spatial interpolation and one for increased I/O performance when using time series.

Checklist

All Merge Requests:

• Update NEWS.txt to describe your changes. I WILL DO THIS AFTER REVIEW
• Run build_telemac.py --check to check Fortran coding conventions.
• Run pylint to check Python coding conventions. NO NEW PYTHON SCRIPTS
• Run build_telemac.py --rebuild for both Release and Debug configurations.
• Run validate_telemac.py for both Release and Debug builds.
• Run validate_telemac.py --notebook for both Release and Debug builds. NO NEW NOTEBOOK
• Run doc_telemac.py if there are any modifications in the documentation.
• Run damocles.py --eficas if there are any modifications in the dictionaries. NO MODIFICATION IN DICO

In addition, for a new feature:

• Check that your feature works in both serial and parallel modes.
• Add at least one test case to check the functionality (with documentation, graphics and VnV script)
• Update the documentation for the module in which your feature will be available.