allow to re-run finetunes when a new version of the fine tuning code is ready

[lukemarsden]

we should have a manual script that we can run when we want to cause finetunes to get re-run with a newer version of our fine tuning code

this should automatically re-finetune all the {text,image} finetunes in the system and then notify the user that their new bots are ready for testing, also cc'ing [email protected]

[lukemarsden]

Will probably want to add notification settings to users profiles, so they can choose to opt out of these emails, and mentioned the fact that they can do that in the email of course with a link to it