[2.4.0] Checkmk Werk 16200 created: mk_informix: Add example configuration

[//]: # (werk v2) # mk_informix: Add example configuration key | value ---------- | --- date | 2024-03-11T12:28:06+00:00 version | 2.4.0b1 class | fix edition | cre component | checks level | 1 compatible | yes Add an example configuration file to showcase how mk_informix can be configured. The `EXCLUDES_INFORMIX-INSTANCE` option mentioned in werk #4580 is not included since this option is not considered in the current implementation.