util.ErrNotFound is currently equal to datastore.ErrNotFound, which is sometimes convenient, but a lot of the time it results in confusing log messages where we cant find a value in the network and "datastore: key not found" gets printed to the logs. I propose we made ErrNotFound its own error and then introduce a function in util called "IsErrNotFound()" that returns true if the given error is our ErrNotFound or the datastore ErrNotFound (or any other not found error from whatever library we might be using)