[2.3.0] Checkmk Werk 17109 created: More helpful error handling for broken plugins

[//]: # (werk v2) # More helpful error handling for broken plugins key | value ---------- | --- date | 2024-06-22T20:52:10+00:00 version | 2.3.0p8 class | fix edition | cre component | checks level | 1 compatible | yes This only affects developers of plugins. In case of a broken import in a plugin the resulting `ImportError` has been swallowed, making debugging very hard. Now the error is reported on the console (to std error), and raised in debug mode (as is the case for any other exception).