MAX_NAME_LENGTH is too short

[wrpscott]

An API call by the Micall watcher, micall.monitor.kive_watcher.find_kive_dataset(), to Kive failed with:
and error:
[WARNING]kiveapi._validate_response(): Error response 400 for https://kive-int.cfenet.ubc.ca/api/runs/: {"name":["Ensure this field has no more than 60 characters."]}

librarian.models.Dataset.name is a CharField of length constants.maxlengths.MAX_FILENAME_LENGTH
currently set to 60.
Given legitimate need for longer file names, we should increase this size.

[donkirkby]

This is a duplicate of cfe-lab/MiCall#451. The problem is the run name, not the dataset name.