The -file param should deserve implementing bash autocompletion

The -file param should deserve implementing bash autocompletion
Found in 1.4.0

Write this command (use the Tab key to autocomplete):
$ kapacitor define mem_alert -file mem_template_task.yaml

Current status:
-file argument is not offered to be autocompleted

$ kapacitor define mem_alert -
-dbrp -no-reload -template -tick -type -vars
ivan@ivan-HP-ZBook-15-G2:~/influx-data$ kapacitor define mem_alert -

Desired status:
the -file option should be in the list

Start with the CLI entry point for `kapacitor define` and trace how its bash completion options are generated. Verify the `-file` option appears when completing `kapacitor define mem_alert -`; completion should list it alongside the existing flags.

Written by the indexing model from the issue text.