Prompt user to delete tale with running instances

[craig-willis]

See whole-tale/girder_wholetale#506 for backend implementation

Problem:
If I delete or unshare/reduce permissions on when another user has an existing tale instance, the instance is not currently shutdown. whole-tale/girder_wholetale#506 fixes this. For the delete case, delete returns a 409 if instances exist and adds a new force parameter to shutdown anyway. We need to handle this in the UI. In the case of 409 on delete notify the user that other users have instances running and allow them to force delete or cancel.

[Xarthisius]

whole-tale/girder_wholetale#506 was updated and now it also applies to Tale > Share tab.