Investigate grouping options together in CLI help text

[danxmoran]

Many of our CLI commands (especially influxd run and influxd upgrade) take a large number of options. Options were often added organically over time, without a consistent naming scheme, so it can end up being difficult for users to know which options are related to one another and how they relate.

A common technique I've seen in other CLI programs is to group options into categories within the help-text. For example, in influxd upgrade we could have groups for "Inputs" and "Outputs". cobra doesn't have built-in support for that functionality, but from spf13/cobra#1327 it sounds like there are enough customization hooks for us to roll our own solution.