AIFS mono support

To run inference on checkpoints that were made with the old version of Anemoi (aifs-mono repository), you need to install some older dependencies. Do the following:

pip install -e .
pip install git+https://github.com/metno/anemoi-models.git@feature/fix-memory-inference-chunking
pip install git+ssh://git@github.com/metno/aifs-mono.git@production

The last two lines will overwrite anemoi-models and will install the aifs package.