Wrap long descriptions, rewording and cosmetics.

Signed-off-by: Daira Hopwood <daira@leastauthority.com>
Fix a bug (no "deployment" config option).

Signed-off-by: Daira Hopwood <daira@leastauthority.com>
Add parameters for AMI image ID and instance size.

Signed-off-by: Daira Hopwood <daira@leastauthority.com>