Description of the enhancement request

When importing from external contest sources, we import static data (e.g. teams, problems info) as well and sometimes update it (e.g. timelimit on problems).

The goal you want to achieve

The number of times data is updated (vs created) is low and should be logged somewhere.

This is especially true for static data, but might make sense for dynamic data as well.

Expected behaviour

Log changes to (static) data when importing from an external source in a non-spammy way. Not sure whether there event feed import script should log this to the console or whether we log it into the DB somewhere (is this already in the auditlog? Can we just set up a special filter there?)