Improve error message when acting on a service that isn't loaded
Improve error message when acting on a service that isn't loaded

This will clarify the error message returned when you attempt to start
or stop a service which is not loaded. The previous error didn't contain
any messaging around `loaded` vs `unloaded` state and just messaged that
a service could not be located.

In addition, all other messages have been updated to reflect the same
messaging when attempting to act on a service which has not been loaded.

Signed-off-by: Jamie Winsor <b4dde37aa2aac745c0e6c43447507eaeace3e59f@vialstudios.com>

rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat