Possibility to add AeroVal to PyESMTools

[andrearosendahl]

The AeroVal diagnostics outputs .json files that are transferred from nird to lustre and shown on the interactive website AeroVal. Transferring the output to lustre requires a MET account, which can not be part of the PyESMTools workflow.

One possibility, however, could be to include a conversion from .json to .png files and an index similar to ADF/run_diag in the diagnostics workflow such that the output can be shown on the website with the other diagnostics. If the output is always saved in the same folder, we can set up an rsync to lustre so that the output can also be seen on AeroVal and therefore also be interactive.