Add '--csv' option to hql.py
Add '--csv' option to 'group list'
Add '--csv' option to 'user list'
Add '--csv' option to 'ldap list'
Refactor `--csv` to `--style=csv` with helper method

In order to enable future styles (tsv, plain, etc),
I went ahead and used the longer version of this to
prevent future noise.
Add PlainStyle for CLI commands

Like `--csv` but omits the header so that
`tail -n +2` is not necessary.