Chronograf 1.11 - tab completion for command line tools would be nice

While testing PR #6211 I needed to work with the `./chronoctl` CLI utility. I noted that tab completion in bash for long commands like `$ ./chronoctl gen-secrets-master-key` was not available.

With long commands and options tab completion would be NICE to have.

Start by examining the ./chronoctl CLI mentioned in the issue and the command used while testing PR #6211. Check how its long commands and options are exposed to bash, then determine the completion scope and how it can be verified. Done means bash tab completion works for the relevant chronoctl commands and options.

Written by the indexing model from the issue text.