Change branding to RH build of Apicurio Registry for 2.6

[EricWittmann]

To summarize, the user docs have been rebranded:

• RH Integration Service Registry: https://access.redhat.com/documentation/en-us/red_hat_integration/2023.q3
• RH build of Apicurio Registry: https://access.redhat.com/documentation/en-us/red_hat_build_of_apicurio_registry/2.4

We also need to rebrand the following:

• RHI Service Registry software download artifacts: https://access.redhat.com/jbossnetwork/restricted/listSoftware.html?downloadType=distributions&product=red.hat.integration&version=2023-Q3
• RHI Service Registry software container images (5 entries in catalog): https://catalog.redhat.com/search?gs&q=red%20hat%20integration%20service%20registry

Note that the empty RHBOAR download category is already created: https://access.redhat.com/jbossnetwork/restricted/listSoftware.html?downloadType=distributions&product=rhboar

We will no longer update the RHI Service Registry user docs in 2024, as RHI is replaced by RHAF, so we will need to rebrand and test the downloads and images before any 2024 release. Thanks!