Replace outdated hostname v1 property for keycloak dev service in shared networks

[HerrDerb]

#45793

Fix keycloak dev service for shared network use.
Remove deprecated and already removed hostname v1 property and configure according hostname v2.

TBD: Tests (quarkusIntTest -Dquarkus.container-image.build=true) to ensure functionality in future?

[sberyozkin]

Thanks @HerrDerb, I've opened a dedicated issue to get the test restored

[quarkus-bot]

Status for workflow Quarkus CI

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It should be safe to merge provided you have a look at the other checks in the summary.

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