Let the icinga check command also output the error when hlast reload failed

[dgoetz]

Is your feature request related to a problem? Please describe.

With an externally hosted satellite like NWS provides it, it is not always possible to log into the system and run the config validation on your own. Solving such an issue involves then support calls and needs more time than it should require.

Describe the solution you'd like

The icinga check command already warns you when the last reload attempt fails. Having the config validation or at least the error message as long output would be great.

Describe alternatives you've considered

I do not see a reason to have this optional, but perhaps it makes sense to have this additional output only when switching a parameter verbose to true, because most people can verify it on CLI?

Additional context

ref/NC/619027

[dnsmichi]

I played around with that while implementing the improved cluster sync - imho it is too verbose inside the icinga check, so I just left it available inside the REST API for debugging calls.