Notify users about potential downgrades based on aws rightsizing recommendations

Frappe Cloud operators act on [right-sizing recommendations](https://github.com/frappe/press/blob/develop/press/press/report/aws_rightsizing_recommendation/aws_rightsizing_recommendation.py).

Show this information to the server owners, so they can save some money.

Currently, this focuses on an extremely low CPU utilisation. AWS doesn't recommend a memory downgrade if the VM is allocating a lot of memory (but not using it), e.g. unnecessarily larger innodb-buffer pools. Later, we can detect large with an extremely high buffer-pool by a very high cache hit rate.

Start with press/press/report/aws_rightsizing_recommendation/aws_rightsizing_recommendation.py and trace how its recommendations could reach server owners. Focus on the currently described low-CPU-utilisation case; done means owners can see the potential downgrade information and use it to identify savings.

Written by the indexing model from the issue text.