The SHC returns public information without pairing.
If we assume that both - SHC and OpenHAB - have IPs in the same network it should be possible find with a simple try & error approach.
I suggest to add/implement this later, after this PR, via a SHC bridge discovery service.
Would it be possible to discover the IP address automatically? If not we could add a link to the official Bosch support page which describes how to find out the IP: https://www.bosch-smarthome.com/de/de/service/bei-der-erstinstallation-werde-ich-nach-der-ip-adresse-des-shc-gefragt
We could ask in the Bosch GitHub repository (https://github.com/BoschSmartHome/bosch-shc-api-docs) how an automatic discovery could be done. The official Bosch Smart Home app does it as well, so it might be possible: https://tt-smarthome.resource.bosch.com/documents/Manual/UK/System_Solutions/Controller_EN_161109_web.pdf
Feedback from @GerdZanker :